Saturday, January 21, 2012

M900 Transmission update

  • Download the latest version of Transmission and libevent from http://ipkg.nslu2-linux.org/feeds/optware/oleg/cross/stable/
  • Find out the IP address of the EAGET M900.
  • Enable the NAS function on the M900 box than execute command explorer \\ipaddress from strat/run menu.
  • Copy and paste the two files downloaded before to poped up filemanager
  • Use putty open a telnet session to the IP address of M900

  • Logo in as root and go to directory of the two uploaded files. by execute cd \tmp\hdd\volume\HDD1\directory name
  • execute ipkg-lc install packagename.ipk -force-reinstall 
  • Add your PC's IP address to the whitelist section of configuration file settings.json which in directory /tmp/hdd/root/etc/transmission. If there are more than one IP address, separate by :
  • Reboot the M900 then test the transmission.

M900 BT Guide

  • To download BT files using M900, you need first get bt seed "*.torrent" file ready. 




  • fire up your internet browser, type in http://10.0.0.42:9091(replace 10.0.0.42 with your M900 ip address).
  • click "Open" which on the top left of the page.Then press "Choose Files" button  and select your *.torrent file in the pop up window. 




  • finally make sure "start when added" is ticked before press the "Upload" button.  see in 3.png



  • Now you could see the downloading status in the web page. 




    Tuesday, July 27, 2010

    Examples of chown

    • Change the ownership to dodo and the group dodo on a file named test.txt
      chown dodo:dodo test.txt

    Man Page of chown

    NAME
           chown - change file owner and group

    SYNOPSIS
           chown [OPTION]... [OWNER][:[GROUP]] FILE...
           chown [OPTION]... --reference=RFILE FILE...

    DESCRIPTION
           This manual page documents the GNU version of chown.  chown changes the
           user and/or group ownership of each given file.  If only  an  owner  (a
           user  name or numeric user ID) is given, that user is made the owner of
           each given file, and the files' group is not changed.  If the owner  is
           followed  by  a  colon  and a group name (or numeric group ID), with no
           spaces between them, the group ownership of the  files  is  changed  as
           well.  If a colon but no group name follows the user name, that user is
           made the owner of the files and the group of the files  is  changed  to
           that  user's  login  group.   If the colon and group are given, but the
           owner is omitted, only the group of the files is changed; in this case,
           chown  performs  the same function as chgrp.  If only a colon is given,
           or if the entire operand is empty, neither the owner nor the  group  is
           changed.

    OPTIONS
           Change the owner and/or group of each FILE to OWNER and/or GROUP.  With
           --reference, change the owner and group of each FILE to those of RFILE.

           -c, --changes
                  like verbose but report only when a change is made

           --dereference
                  affect the referent of each symbolic link (this is the default),
                  rather than the symbolic link itself

           -h, --no-dereference
                  affect each symbolic link instead of any referenced file (useful
                  only on systems that can change the ownership of a symlink)

           --from=CURRENT_OWNER:CURRENT_GROUP
                  change  the  owner and/or group of each file only if its current
                  owner and/or group match those specified here.   Either  may  be
                  omitted,  in  which case a match is not required for the omitted
                  attribute.

           --no-preserve-root
                  do not treat `/' specially (the default)

           --preserve-root
                  fail to operate recursively on `/'

           -f, --silent, --quiet
                  suppress most error messages

           --reference=RFILE
                  use RFILE's owner and group rather than  specifying  OWNER:GROUP
                  values

           -R, --recursive
                  operate on files and directories recursively

           -v, --verbose
                  output a diagnostic for every file processed

           The  following  options modify how a hierarchy is traversed when the -R
           option is also specified.  If more than  one  is  specified,  only  the
           final one takes effect.

           -H     if  a  command  line argument is a symbolic link to a directory,
                  traverse it

           -L     traverse every symbolic link to a directory encountered

           -P     do not traverse any symbolic links (default)

           --help display this help and exit

           --version
                  output version information and exit

           Owner is unchanged if missing.  Group  is  unchanged  if  missing,  but
           changed  to login group if implied by a `:' following a symbolic OWNER.
           OWNER and GROUP may be numeric as well as symbolic.

    EXAMPLES
           chown root /u
                  Change the owner of /u to "root".

           chown root:staff /u
                  Likewise, but also change its group to "staff".

           chown -hR root /u
                  Change the owner of /u and subfiles to "root".

    AUTHOR
           Written by David MacKenzie and Jim Meyering.

    REPORTING BUGS
           Report chown bugs to bug-coreutils@gnu.org
           GNU coreutils home page:
           General help using GNU software:

    COPYRIGHT
           Copyright © 2009 Free Software Foundation, Inc.   License  GPLv3+:  GNU
           GPL version 3 or later .
           This  is  free  software:  you  are free to change and redistribute it.
           There is NO WARRANTY, to the extent permitted by law.

    SEE ALSO
           chown(2)

           The full documentation for chown is maintained as a Texinfo manual.  If
           the  info  and  chown programs are properly installed at your site, the
           command

                  info coreutils 'chown invocation'

           should give you access to the complete manual.



    GNU coreutils 7.1                October 2009                         CHOWN(1)






    Back to linux LPIC1 Exam Objectives

    Man Page of quotaon

    NAME
           quotaon, quotaoff - turn filesystem quotas on and off

    SYNOPSIS
           /sbin/quotaon [ -vugfp ] [ -F format-name ] filesystem...
           /sbin/quotaon [ -avugfp ] [ -F format-name ]

           /sbin/quotaoff [ -vugp ] [ -x state ] filesystem...
           /sbin/quotaoff [ -avugp ]

    DESCRIPTION
       quotaon
           quotaon  announces  to the system that disk quotas should be enabled on
           one or more filesystems. The filesystem quota files must be present  in
           the  root  directory  of  the  specified filesystem and be named either
           aquota.user (for version 2 user quota), quota.user (for version 1  user
           quota),  aquota.group  (for version 2 group quota), or quota.group (for
           version 1 group quota).

           XFS filesystems are a special case - XFS considers quota information as
           filesystem metadata and uses journaling to provide a higher level guar-
           antee of consistency.  There are two components to the XFS  disk  quota
           system: accounting and limit enforcement.  XFS filesystems require that
           quota accounting be turned on at mount time.  It is possible to  enable
           and disable limit enforcement on an XFS filesystem after quota account-
           ing is already turned on.  The default is to turn  on  both  accounting
           and enforcement.

           The  XFS  quota  implementation  does not maintain quota information in
           user-visible files, but rather stores this information internally.

       quotaoff
           quotaoff announces to the system that the specified filesystems  should
           have any disk quotas turned off.

    OPTIONS
       quotaon
           -F, --format=format-name
                  Report  quota  for  specified  format  (ie. don't perform format
                  autodetection).  Possible format names are:  vfsold  (version  1
                  quota), vfsv0 (version 2 quota), xfs (quota on XFS filesystem)

           -a, --all
                  All automatically mounted (no noauto option) non-NFS filesystems
                  in /etc/fstab with quotas will  have  their  quotas  turned  on.
                  This is normally used at boot time to enable quotas.

           -v, --verbose
                  Display  a  message  for each filesystem where quotas are turned
                  on.

           -u, --user
                  Manipulate user quotas. This is the default.

           -g, --group
                  Manipulate group quotas.

           -p, --print-state
                  Instead of turning quotas on just print  state  of  quotas  (ie.
                  whether. quota is on or off)

           -f, --off
                  Make quotaon behave like being called as quotaoff.

       quotaoff
           -F, --format=format-name
                  Report  quota  for  specified  format  (ie. don't perform format
                  autodetection).  Possible format names are:  vfsold  (version  1
                  quota), vfsv0 (version 2 quota), xfs (quota on XFS filesystem)

           -a, --all
                  Force  all  filesystems  in /etc/fstab to have their quotas dis-
                  abled.

           -v, --verbose
                  Display a message for each filesystem affected.

           -u, --user
                  Manipulate user quotas. This is the default.

           -g, --group
                  Manipulate group quotas.

           -p, --print-state
                  Instead of turning quotas off just print state  of  quotas  (ie.
                  whether. quota is on or off)

           -x, --xfs-command delete
                  Free  up  the  space  used to hold quota information (maintained
                  internally) within XFS.  This option is only applicable to  XFS,
                  and is silently ignored for other filesystem types.  It can only
                  be used on a filesystem with quota previously turned off.

           -x, --xfs-command enforce
                  Switch on/off limit enforcement  for  XFS  filesystems  (perform
                  quota  accounting only).  This option is only applicable to XFS,
                  and is silently ignored for other filesystem types.

    NOTES ON XFS FILESYSTEMS
           To enable quotas on an XFS filesystem, use mount(8) or /etc/fstab quota
           option  to enable both accounting and limit enforcement.  quotaon util-
           ity cannot be used for this purpose.

           Turning on quotas on an XFS root filesystem requires  the  quota  mount
           options  be passed into the kernel at boot time through the Linux root-
           flags boot option.

           To turn off quota limit enforcement on any XFS filesystem,  first  make
           sure  that  quota  accounting  and enforcement are both turned on using
           repquota -v filesystem.  Then, use quotaoff -v  filesystem  to  disable
           limit enforcement.  This may be done while the filesystem is mounted.

           Turning  on  quota  limit  enforcement on an XFS filesystem is achieved
           using quotaon -v filesystem.  This may be done while the filesystem  is
           mounted.

    FILES
           aquota.user or aquota.group
                               quota file at the filesystem root (version 2 quota,
                               non-XFS filesystems)
           quota.user or quota.group
                               quota file at the filesystem root (version 1 quota,
                               non-XFS filesystems)
           /etc/fstab          default filesystems

    SEE ALSO
           quotactl(2), fstab(5), quota_nld(8), repquota(8), warnquota(8)



    4th Berkeley Distribution                                           QUOTAON(8)


    Back to linux LPIC1 Exam Objectives

    Man Page of repquota

    NAME
           repquota - summarize quotas for a filesystem

    SYNOPSIS
           /usr/sbin/repquota [ -vspiug ] [ -c | -C ] [ -t | -n ] [ -F format-name
           ] filesystem...

           /usr/sbin/repquota [ -avtpsiug ] [ -c | -C ] [ -t | -n ] [  -F  format-
           name ]

    DESCRIPTION
           repquota  prints  a summary of the disc usage and quotas for the speci-
           fied file systems.  For each user  the  current  number  of  files  and
           amount  of  space (in kilobytes) is printed, along with any quotas cre-
           ated with  edquota(8).   As  repquota  has  to  translate  ids  of  all
           users/groups  to  names  (unless option -n was specified) it may take a
           while to print all the information. To make translating as fast as pos-
           sible  repquota tries to detect (by reading /etc/nsswitch.conf) whether
           entries are stored in standard plain  text  file  or  in  database  and
           either  translates  chunks of 1024 names or each name individually. You
           can override this autodetection by -c or -C options.

    OPTIONS
           -a, --all
                  Report on all filesystems indicated in  /etc/mtab  to  be  read-
                  write with quotas.

           -v, --verbose
                  Report  all quotas, even if there is no usage. Be also more ver-
                  bose about quotafile information.

           -c, --batch-translation
                  Cache entries to report and translate uids/gids to names in  big
                  chunks  by  scanning  all  users  (default). This is good (fast)
                  behaviour when using /etc/passwd file.

           -C, --no-batch-translation
                  Translate individual entries. This is faster when you have users
                  stored in database.

           -t, --truncate-names
                  Truncate user/group names longer than 9 characters. This results
                  in nicer output when there are such names.

           -n, --no-names
                  Don't resolve UIDs/GIDs to names. This can  speedup  printing  a
                  lot.

           -s, --human-readable
                  Try  to  report  used space, number of used inodes and limits in
                  more appropriate units than the default ones.

           -p, --raw-grace
                  When user is in grace period, report time in seconds since epoch
                  when his grace time runs out (or has run out). Field is '0' when
                  no grace time is in effect.   This  is  especially  useful  when
                  parsing output by a script.

           -i, --no-autofs
                  Ignore mountpoints mounted by automounter.

           -F, --format=format-name
                  Report  quota  for  specified  format  (ie. don't perform format
                  autodetection).  Possible format names are:  vfsold  (version  1
                  quota), vfsv0 (version 2 quota), xfs (quota on XFS filesystem)

           -g, --group
                  Report quotas for groups.

           -u, --user
                  Report quotas for users. This is the default.

           Only the super-user may view quotas which are not their own.

    FILES
           aquota.user or aquota.group
                               quota file at the filesystem root (version 2 quota,
                               non-XFS filesystems)
           quota.user or quota.group
                               quota file at the filesystem root (version 1 quota,
                               non-XFS filesystems)
           /etc/mtab           default filesystems
           /etc/passwd         default set of users
           /etc/group          default set of groups

    SEE ALSO
           quota(1),    quotactl(2),    edquota(8),   quotacheck(8),   quotaon(8),
           quota_nld(8), setquota(8), warnquota(8)

    4th Berkeley Distribution                                          REPQUOTA(8)


    Back to linux LPIC1 Exam Objectives

    Man Page of edquota

    NAME
           edquota - edit user quotas

    SYNOPSIS
           edquota  [  -p  protoname ] [ -u | -g ] [ -rm ] [ -F format-name ] [ -f
           filesystem ] username...

           edquota [ -u | -g ] [ -F format-name ] [ -f filesystem ] -t

           edquota [ -u | -g ] [ -F format-name ] [ -f filesystem ] -T  username |
           groupname...

    DESCRIPTION
           edquota  is  a quota editor.  One or more users or groups may be speci-
           fied on the command line.  If  a  number  is  given  in  the  place  of
           user/group  name  it is treated as an UID/GID. For each user or group a
           temporary file is created with an ASCII representation of  the  current
           disk quotas for that user or group and an editor is then invoked on the
           file.  The quotas may then be modified, new quotas added, etc.  Setting
           a quota to zero indicates that no quota should be imposed.

           Users are permitted to exceed their soft limits for a grace period that
           may be specified per filesystem.  Once the grace  period  has  expired,
           the soft limit is enforced as a hard limit.

           The  current  usage  information  in the file is for informational pur-
           poses; only the hard and soft limits can be changed.

           Upon leaving the editor, edquota reads the temporary file and  modifies
           the binary quota files to reflect the changes made.

           The  editor  invoked  is  vi(1)  unless either the EDITOR or the VISUAL
           environment variable specifies otherwise.

           Only the super-user may edit quotas.

    OPTIONS
           -r, --remote
                  Edit also non-local quota use rpc.rquotad on  remote  server  to
                  set  quota.   This  option is available only if quota tools were
                  compiled with enabled support for setting quotas over RPC.   The
                  -n option is equivalent, and is maintained for backward compati-
                  bility.

           -m, --no-mixed-pathnames
                  Currently, pathnames of NFSv4 mountpoints are sent without lead-
                  ing slash in the path.  rpc.rquotad uses this to recognize NFSv4
                  mounts and properly prepend pseudoroot of NFS filesystem to  the
                  path.  If  you  specify  this  option, setquota will always send
                  paths with a trailing slash. This can be useful for legacy  rea-
                  sons  but  be aware that quota over RPC will stop working if you
                  are using new rpc.rquotad.

           -u, --user
                  Edit the user quota. This is the default.

           -g, --group
                  Edit the group quota.

           -p, --prototype=protoname
                  Duplicate the quotas of the prototypical user specified for each
                  user specified.  This is the normal mechanism used to initialize
                  quotas for groups of users.

           -F, --format=format-name
                  Edit quota  for  specified  format  (ie.  don't  perform  format
                  autodetection).   Possible  format  names are: vfsold (version 1
                  quota), vfsv0 (version 2  quota),  rpc  (quota  over  NFS),  xfs
                  (quota on XFS filesystem)

           -f, --filesystem filesystem
                  Perform  specified operations only for given filesystem (default
                  is to perform operations for all filesystems with quota).

           -t, --edit-period
                  Edit the soft time limits for each  filesystem.   In  old  quota
                  format  if  the time limits are zero, the default time limits in
                  are used. In new quota format time  limits  must
                  be  specified  (there  is  no default value set in kernel). Time
                  units of 'seconds', 'minutes', 'hours', and  'days'  are  under-
                  stood.  Time  limits  are  printed in the greatest possible time
                  unit such that the value is greater than or equal to one.

           -T, --edit-times
                  Edit time for the user/group when softlimit is enforced.  Possi-
                  ble values are 'unset' or number and unit. Units are the same as
                  in -t option.

    FILES
           aquota.user or aquota.group
                               quota file at the filesystem root (version 2 quota,
                               non-XFS filesystems)
           quota.user or quota.group
                               quota file at the filesystem root (version 1 quota,
                               non-XFS filesystems)
           /etc/mtab           mounted filesystems table

    SEE ALSO
           quota(1), vi(1), quotactl(2), quotacheck(8),  quotaon(8),  repquota(8),
           setquota(8)


    Back to linux LPIC1 Exam Objectives

    Man Page of quota

    QUOTA(1)                                                              QUOTA(1)



    NAME
           quota - display disk usage and limits

    SYNOPSIS
           quota [ -F format-name ] [ -guqvswi ] [ -l | [ -QAm ]]
           quota [ -F format-name ] [ -qvswi ] [ -l | [ -QAm ]] -u user...
           quota [ -F format-name ] [ -qvswi ] [ -l | [ -QAm ]] -g group...
           quota [ -F format-name ] [ -qvswugQm ] -f filesystem...

    DESCRIPTION
           quota  displays users' disk usage and limits.  By default only the user
           quotas are printed.

           quota reports the quotas of all the filesystems  listed  in  /etc/mtab.
           For  filesystems  that are NFS-mounted a call to the rpc.rquotad on the
           server machine is performed to get the information.

    OPTIONS
           -F, --format=format-name
                  Show quota  for  specified  format  (ie.  don't  perform  format
                  autodetection).   Possible  format  names are: vfsold (version 1
                  quota), vfsv0 (version 2  quota),  rpc  (quota  over  NFS),  xfs
                  (quota on XFS filesystem)

           -g, --group
                  Print  group quotas for the group of which the user is a member.
                  The optional group argument(s)  restricts  the  display  to  the
                  specified group(s).

           -u, --user
                  flag is equivalent to the default.

           -v, --verbose
                  will  display  quotas  on  filesystems where no storage is allo-
                  cated.

           -s, --human-readable
                  option will make quota(1) try to choose units for  showing  lim-
                  its, used space and used inodes.

           -p, --raw-grace
                  When user is in grace period, report time in seconds since epoch
                  when his grace time runs out (or has run out). Field is '0' when
                  no  grace  time  is  in  effect.  This is especially useful when
                  parsing output by a script.

           -i, --no-autofs
                  ignore mountpoints mounted by automounter

           -l, --local-only
                  report quotas only on local filesystems (ie. ignore NFS  mounted
                  filesystems).

           -A, --all-nfs
                  report  quotas for all NFS filesystems even if they report to be
                  on the same device.

           -m, --no-mixed-pathnames
                  Currently, pathnames of NFSv4 mountpoints are sent without lead-
                  ing slash in the path.  rpc.rquotad uses this to recognize NFSv4
                  mounts and properly prepend pseudoroot of NFS filesystem to  the
                  path.  If  you  specify  this  option, setquota will always send
                  paths with a trailing slash. This can be useful for legacy  rea-
                  sons  but  be aware that quota over RPC will stop working if you
                  are using new rpc.rquotad.

           -q, --quiet
                  Print a more  terse  message,  containing  only  information  on
                  filesystems where usage is over quota.

           -Q, --quiet-refuse
                  Do  not  print  error  message  if  connection to rpc.rquotad is
                  refused (usually this happens when rpc.rquotad is not running on
                  the server).

           -w, --no-wrap
                  Do not wrap the line if the device name is too long. This can be
                  useful when parsing the output of quota(1) by a script.

           Specifying both -g and -u displays both the user quotas and  the  group
           quotas (for the user).

           Only  the super-user may use the -u flag and the optional user argument
           to view the limits of other users.  Non-super-users can use the the  -g
           flag  and  optional group argument to view only the limits of groups of
           which they are members.

           The -q flag takes precedence over the -v flag.

    DIAGNOSTICS
           If quota exits with a non-zero status, one or more filesystems are over
           quota.

    FILES
           aquota.user  or  aquota.group
                               quota file at the filesystem root (version 2 quota,
                               non-XFS filesystems)
           quota.user  or  quota.group
                               quota file at the filesystem root (version 1 quota,
                               non-XFS filesystems)
           /etc/mtab           default filesystems

    SEE ALSO
           quotactl(2),    fstab(5),    edquota(8),   quotacheck(8),   quotaon(8),
           quota_nld(8), repquota(8),

    Back to linux LPIC1 Exam Objectives

    Monday, July 26, 2010

    examples of grep

    • Only display lines containing capital letters
      grep -n [A-Z] name.txt
    •  
    Back to linux LPIC1 Exam Objectives

      Man Page of grep

      NAME
             grep, egrep, fgrep - print lines matching a pattern

      SYNOPSIS
             grep [OPTIONS] PATTERN [FILE...]
             grep [OPTIONS] [-e PATTERN | -f FILE] [FILE...]

      DESCRIPTION
             grep  searches the named input FILEs (or standard input if no files are
             named, or if a single hyphen-minus (-) is given as file name) for lines
             containing  a  match to the given PATTERN.  By default, grep prints the
             matching lines.

             In addition, two variant programs egrep and fgrep are available.  egrep
             is  the  same  as  grep -E.   fgrep  is  the  same  as grep -F.  Direct
             invocation as either egrep or fgrep is deprecated, but is  provided  to
             allow historical applications that rely on them to run unmodified.

      OPTIONS
         Generic Program Information
             --help Print  a  usage  message  briefly summarizing these command-line
                    options and the bug-reporting address, then exit.

             -V, --version
                    Print the version number of grep to the standard output  stream.
                    This  version  number should be included in all bug reports (see
                    below).

         Matcher Selection
             -E, --extended-regexp
                    Interpret PATTERN as an extended regular  expression  (ERE,  see
                    below).  (-E is specified by POSIX.)

             -F, --fixed-strings
                    Interpret  PATTERN  as  a  list  of  fixed strings, separated by
                    newlines, any of which is to be matched.  (-F  is  specified  by
                    POSIX.)

             -G, --basic-regexp
                    Interpret  PATTERN  as  a  basic  regular  expression  (BRE, see
                    below).  This is the default.

             -P, --perl-regexp
                    Interpret PATTERN as a Perl regular expression.  This is  highly
                    experimental and grep -P may warn of unimplemented features.

         Matching Control
             -e PATTERN, --regexp=PATTERN
                    Use  PATTERN  as  the  pattern.   This  can  be  used to specify
                    multiple search patterns, or to protect a pattern beginning with
                    a hyphen (-).  (-e is specified by POSIX.)

             -f FILE, --file=FILE
                    Obtain  patterns  from  FILE,  one  per  line.   The  empty file
                    contains zero patterns, and therefore matches nothing.   (-f  is
                    specified by POSIX.)

             -i, --ignore-case
                    Ignore  case  distinctions  in  both  the  PATTERN and the input
                    files.  (-i is specified by POSIX.)

             -v, --invert-match
                    Invert the sense of matching, to select non-matching lines.  (-v
                    is specified by POSIX.)

             -w, --word-regexp
                    Select  only  those  lines  containing  matches  that form whole
                    words.  The test is that the matching substring must  either  be
                    at  the  beginning  of  the  line,  or  preceded  by  a non-word
                    constituent character.  Similarly, it must be either at the  end
                    of  the  line  or  followed by a non-word constituent character.
                    Word-constituent  characters  are  letters,  digits,   and   the
                    underscore.

             -x, --line-regexp
                    Select  only  those  matches  that exactly match the whole line.
                    (-x is specified by POSIX.)

             -y     Obsolete synonym for -i.

         General Output Control
             -c, --count
                    Suppress normal output; instead print a count of matching  lines
                    for  each  input  file.  With the -v, --invert-match option (see
                    below), count non-matching lines.  (-c is specified by POSIX.)

             --color[=WHEN], --colour[=WHEN]
                    Surround  the  matched  (non-empty)  strings,  matching   lines,
                    context  lines,  file  names,  line  numbers,  byte offsets, and
                    separators (for fields and groups of context lines) with  escape
                    sequences  to display them in color on the terminal.  The colors
                    are  defined  by  the  environment  variable  GREP_COLORS.   The
                    deprecated  environment  variable GREP_COLOR is still supported,
                    but its setting does not have priority.  WHEN is never,  always,
                    or auto.

             -L, --files-without-match
                    Suppress  normal  output;  instead  print the name of each input
                    file from which no output would normally have been printed.  The
                    scanning will stop on the first match.

             -l, --files-with-matches
                    Suppress  normal  output;  instead  print the name of each input
                    file from which output would normally have  been  printed.   The
                    scanning  will  stop  on  the  first match.  (-l is specified by
                    POSIX.)

             -m NUM, --max-count=NUM
                    Stop reading a file after NUM matching lines.  If the  input  is
                    standard  input  from a regular file, and NUM matching lines are
                    output, grep ensures that the standard input  is  positioned  to
                    just  after the last matching line before exiting, regardless of
                    the presence of trailing context lines.  This enables a  calling
                    process  to resume a search.  When grep stops after NUM matching
                    lines, it outputs any trailing context lines.  When  the  -c  or
                    --count  option  is  also  used,  grep  does  not output a count
                    greater than NUM.  When the -v or --invert-match option is  also
                    used, grep stops after outputting NUM non-matching lines.

             -o, --only-matching
                    Print  only  the  matched  (non-empty) parts of a matching line,
                    with each such part on a separate output line.

             -q, --quiet, --silent
                    Quiet;  do  not  write  anything  to  standard   output.    Exit
                    immediately  with  zero status if any match is found, even if an
                    error was detected.  Also see the -s  or  --no-messages  option.
                    (-q is specified by POSIX.)

             -s, --no-messages
                    Suppress  error  messages about nonexistent or unreadable files.
                    Portability note: unlike GNU grep, 7th Edition Unix grep did not
                    conform to POSIX, because it lacked -q and its -s option behaved
                    like GNU grep's -q option.  USG-style grep also  lacked  -q  but
                    its  -s  option  behaved  like GNU grep.  Portable shell scripts
                    should avoid both -q and -s and  should  redirect  standard  and
                    error  output to /dev/null instead.  (-s is specified by POSIX.)

         Output Line Prefix Control
             -b, --byte-offset
                    Print the 0-based byte offset within the input file before  each
                    line of output.  If -o (--only-matching) is specified, print the
                    offset of the matching part itself.

             -H, --with-filename
                    Print the file name for each match.  This is  the  default  when
                    there is more than one file to search.

             -h, --no-filename
                    Suppress  the  prefixing  of  file names on output.  This is the
                    default when there is only one file (or only standard input)  to
                    search.

             --label=LABEL
                    Display  input  actually  coming  from  standard  input as input
                    coming from file LABEL.  This is  especially  useful  for  tools
                    like zgrep, e.g., gzip -cd foo.gz | grep --label=foo something

             -n, --line-number
                    Prefix  each  line of output with the 1-based line number within
                    its input file.  (-n is specified by POSIX.)

             -T, --initial-tab
                    Make sure that the first character of actual line  content  lies
                    on a tab stop, so that the alignment of tabs looks normal.  This
                    is useful with options that prefix their output  to  the  actual
                    content:  -H,-n,  and  -b.   In order to improve the probability
                    that lines from a single file will all start at the same column,
                    this also causes the line number and byte offset (if present) to
                    be printed in a minimum size field width.

             -u, --unix-byte-offsets
                    Report Unix-style byte offsets.   This  switch  causes  grep  to
                    report  byte offsets as if the file were a Unix-style text file,
                    i.e., with  CR  characters  stripped  off.   This  will  produce
                    results  identical  to  running  grep  on  a Unix machine.  This
                    option has no effect unless -b option is also used;  it  has  no
                    effect on platforms other than MS-DOS and MS-Windows.

             -Z, --null
                    Output  a  zero  byte  (the  ASCII NUL character) instead of the
                    character that normally follows a file name.  For example,  grep
                    -lZ  outputs  a  zero  byte  after each file name instead of the
                    usual newline.  This option makes the output  unambiguous,  even
                    in the presence of file names containing unusual characters like
                    newlines.  This option can  be  used  with  commands  like  find
                    -print0,  perl  -0,  sort  -z, and xargs -0 to process arbitrary
                    file names, even those that contain newline characters.

         Context Line Control
             -A NUM, --after-context=NUM
                    Print NUM  lines  of  trailing  context  after  matching  lines.
                    Places   a  line  containing  a  group  separator  (--)  between
                    contiguous groups of matches.  With the  -o  or  --only-matching
                    option, this has no effect and a warning is given.

             -B NUM, --before-context=NUM
                    Print  NUM  lines  of  leading  context  before  matching lines.
                    Places  a  line  containing  a  group  separator  (--)   between
                    contiguous  groups  of  matches.  With the -o or --only-matching
                    option, this has no effect and a warning is given.

             -C NUM, -NUM, --context=NUM
                    Print NUM lines of output context.  Places a line  containing  a
                    group separator (--) between contiguous groups of matches.  With
                    the -o or --only-matching option,  this  has  no  effect  and  a
                    warning is given.

         File and Directory Selection
             -a, --text
                    Process  a binary file as if it were text; this is equivalent to
                    the --binary-files=text option.

             --binary-files=TYPE
                    If the first few bytes of a file indicate that the file contains
                    binary  data, assume that the file is of type TYPE.  By default,
                    TYPE is binary, and grep  normally  outputs  either  a  one-line
                    message  saying  that  a  binary  file matches, or no message if
                    there is no match.  If TYPE is without-match, grep assumes  that
                    a  binary  file  does  not  match;  this is equivalent to the -I
                    option.  If TYPE is text, grep processes a binary file as if  it
                    were  text;  this is equivalent to the -a option.  Warning: grep
                    --binary-files=text might output binary garbage, which can  have
                    nasty  side  effects  if  the  output  is  a terminal and if the
                    terminal driver interprets some of it as commands.

             -D ACTION, --devices=ACTION
                    If an input file is a device, FIFO  or  socket,  use  ACTION  to
                    process  it.   By  default,  ACTION  is  read,  which means that
                    devices are read just as if they were ordinary files.  If ACTION
                    is skip, devices are silently skipped.

             -d ACTION, --directories=ACTION
                    If  an  input file is a directory, use ACTION to process it.  By
                    default, ACTION is read, which means that directories  are  read
                    just  as  if  they  were  ordinary  files.   If  ACTION is skip,
                    directories are silently skipped.  If ACTION  is  recurse,  grep
                    reads  all  files  under  each  directory,  recursively; this is
                    equivalent to the -r option.

             --exclude=GLOB
                    Skip  files  whose  base  name  matches  GLOB  (using   wildcard
                    matching).   A  file-name  glob  can  use  *,  ?,  and [...]  as
                    wildcards, and \ to quote  a  wildcard  or  backslash  character
                    literally.

             --exclude-from=FILE
                    Skip  files  whose  base name matches any of the file-name globs
                    read from FILE  (using  wildcard  matching  as  described  under
                    --exclude).

             --exclude-dir=DIR
                    Exclude  directories  matching  the  pattern  DIR from recursive
                    searches.

             -I     Process a binary file as if it did not  contain  matching  data;
                    this is equivalent to the --binary-files=without-match option.

             --include=GLOB
                    Search  only  files whose base name matches GLOB (using wildcard
                    matching as described under --exclude).

             -R, -r, --recursive
                    Read all  files  under  each  directory,  recursively;  this  is
                    equivalent to the -d recurse option.

         Other Options
             --line-buffered
                    Use  line  buffering  on  output.   This can cause a performance
                    penalty.

             --mmap If possible, use the mmap(2) system call to read input,  instead
                    of  the default read(2) system call.  In some situations, --mmap
                    yields better performance.  However, --mmap can cause  undefined
                    behavior  (including  core dumps) if an input file shrinks while
                    grep is operating, or if an I/O error occurs.

             -U, --binary
                    Treat the file(s) as binary.  By default, under MS-DOS  and  MS-
                    Windows,  grep  guesses the file type by looking at the contents
                    of the first 32KB read from the file.  If grep decides the  file
                    is  a  text  file, it strips the CR characters from the original
                    file contents (to make regular expressions with  ^  and  $  work
                    correctly).  Specifying -U overrules this guesswork, causing all
                    files to be read and passed to the matching mechanism  verbatim;
                    if  the  file is a text file with CR/LF pairs at the end of each
                    line, this will cause some regular expressions  to  fail.   This
                    option  has  no  effect  on  platforms other than MS-DOS and MS-
                    Windows.

             -z, --null-data
                    Treat the input as a set of lines, each  terminated  by  a  zero
                    byte  (the  ASCII NUL character) instead of a newline.  Like the
                    -Z or --null option, this option can be used with commands  like
                    sort -z to process arbitrary file names.

      REGULAR EXPRESSIONS
             A  regular  expression  is  a  pattern that describes a set of strings.
             Regular  expressions  are   constructed   analogously   to   arithmetic
             expressions, by using various operators to combine smaller expressions.

             grep understands two different versions of regular  expression  syntax:
             “basic”  and  “extended.”   In  GNU grep,  there  is  no  difference in
             available functionality using either syntax.  In other implementations,
             basic regular expressions are less powerful.  The following description
             applies to extended regular expressions; differences for basic  regular
             expressions are summarized afterwards.

             The  fundamental building blocks are the regular expressions that match
             a single character.  Most characters, including all letters and digits,
             are regular expressions that match themselves.  Any meta-character with
             special meaning may be quoted by preceding it with a backslash.

             The period . matches any single character.

         Character Classes and Bracket Expressions
             A bracket expression is a list of characters enclosed by [ and  ].   It
             matches  any  single  character in that list; if the first character of
             the list is the caret ^ then it matches any character not in the  list.
             For  example,  the  regular  expression [0123456789] matches any single
             digit.

             Within a  bracket  expression,  a  range  expression  consists  of  two
             characters separated by a hyphen.  It matches any single character that
             sorts  between  the  two  characters,  inclusive,  using  the  locale's
             collating  sequence  and  character set.  For example, in the default C
             locale, [a-d] is equivalent to [abcd].  Many locales sort characters in
             dictionary   order,  and  in  these  locales  [a-d]  is  typically  not
             equivalent to [abcd]; it might be equivalent to [aBbCcDd], for example.
             To  obtain  the  traditional interpretation of bracket expressions, you
             can use the C locale by setting the LC_ALL environment variable to  the
             value C.

             Finally,  certain  named  classes  of  characters are predefined within
             bracket expressions, as follows.  Their names are self explanatory, and
             they   are   [:alnum:],  [:alpha:],  [:cntrl:],  [:digit:],  [:graph:],
             [:lower:], [:print:], [:punct:], [:space:], [:upper:], and  [:xdigit:].
             For  example,  [[:alnum:]]  means  [0-9A-Za-z],  except the latter form
             depends upon the C locale and the ASCII character encoding, whereas the
             former  is  independent  of  locale  and character set.  (Note that the
             brackets in these class names are part of the symbolic names, and  must
             be  included  in  addition  to  the  brackets  delimiting  the  bracket
             expression.)  Most meta-characters lose their  special  meaning  inside
             bracket  expressions.   To  include  a  literal ] place it first in the
             list.  Similarly, to include a literal ^ place it anywhere  but  first.
             Finally, to include a literal - place it last.

         Anchoring
             The caret ^ and the dollar sign $ are meta-characters that respectively
             match the empty string at the beginning and end of a line.

         The Backslash Character and Special Expressions
             The symbols \< and \>  respectively  match  the  empty  string  at  the
             beginning and end of a word.  The symbol \b matches the empty string at
             the edge of a word, and \B matches the empty string provided  it's  not
             at  the edge of a word.  The symbol \w is a synonym for [[:alnum:]] and
             \W is a synonym for [^[:alnum:]].

         Repetition
             A regular expression may be  followed  by  one  of  several  repetition
             operators:
             ?      The preceding item is optional and matched at most once.
             *      The preceding item will be matched zero or more times.
             +      The preceding item will be matched one or more times.
             {n}    The preceding item is matched exactly n times.
             {n,}   The preceding item is matched n or more times.
             {,m}   The preceding item is matched at most m times.
             {n,m}  The  preceding  item  is  matched at least n times, but not more
                    than m times.

         Concatenation
             Two regular expressions may  be  concatenated;  the  resulting  regular
             expression  matches  any  string formed by concatenating two substrings
             that respectively match the concatenated expressions.

         Alternation
             Two regular expressions may be joined by  the  infix  operator  |;  the
             resulting   regular  expression  matches  any  string  matching  either
             alternate expression.

         Precedence
             Repetition takes precedence over concatenation,  which  in  turn  takes
             precedence  over  alternation.   A  whole expression may be enclosed in
             parentheses  to  override   these   precedence   rules   and   form   a
             subexpression.

         Back References and Subexpressions
             The back-reference \n, where n is a single digit, matches the substring
             previously matched  by  the  nth  parenthesized  subexpression  of  the
             regular expression.

         Basic vs Extended Regular Expressions
             In  basic  regular expressions the meta-characters ?, +, {, |, (, and )
             lose their special meaning; instead use the  backslashed  versions  \?,
             \+, \{, \|, \(, and \).

             Traditional  egrep did not support the { meta-character, and some egrep
             implementations support \{ instead, so portable scripts should avoid  {
             in grep -E patterns and should use [{] to match a literal {.

             GNU grep -E attempts to support traditional usage by assuming that { is
             not  special  if  it  would  be  the  start  of  an  invalid   interval
             specification.   For example, the command grep -E '{1' searches for the
             two-character string {1 instead of reporting  a  syntax  error  in  the
             regular  expression.  POSIX.2 allows this behavior as an extension, but
             portable scripts should avoid it.

      ENVIRONMENT VARIABLES
             The  behavior  of  grep  is  affected  by  the  following   environment
             variables.

             The  locale  for  category  LC_foo  is specified by examining the three
             environment variables LC_ALL, LC_foo, LANG, in that order.   The  first
             of  these  variables that is set specifies the locale.  For example, if
             LC_ALL is not set, but LC_MESSAGES is set to pt_BR, then the  Brazilian
             Portuguese  locale  is used for the LC_MESSAGES category.  The C locale
             is used if none of these environment variables are set, if  the  locale
             catalog  is  not  installed,  or if grep was not compiled with national
             language support (NLS).

             GREP_OPTIONS
                    This variable specifies default options to be placed in front of
                    any   explicit   options.    For  example,  if  GREP_OPTIONS  is
                    '--binary-files=without-match --directories=skip', grep  behaves
                    as   if   the   two   options  --binary-files=without-match  and
                    --directories=skip  had  been  specified  before  any   explicit
                    options.   Option specifications are separated by whitespace.  A
                    backslash escapes the next character,  so  it  can  be  used  to
                    specify an option containing whitespace or a backslash.

             GREP_COLOR
                    This  variable  specifies  the  color  used to highlight matched
                    (non-empty) text.  It is deprecated in favor of GREP_COLORS, but
                    still supported.  The mt, ms, and mc capabilities of GREP_COLORS
                    have priority over it.  It can only specify the  color  used  to
                    highlight  the  matching  non-empty text in any matching line (a
                    selected line when the -v command-line option is omitted,  or  a
                    context line when -v is specified).  The default is 01;31, which
                    means a bold red  foreground  text  on  the  terminal's  default
                    background.

             GREP_COLORS
                    Specifies  the  colors  and  other  attributes used to highlight
                    various parts of the output.  Its  value  is  a  colon-separated
                    list       of       capabilities      that      defaults      to
                    ms=01;31:mc=01;31:sl=:cx=:fn=35:ln=32:bn=32:se=36  with  the  rv
                    and  ne  boolean  capabilities omitted (i.e., false).  Supported
                    capabilities are as follows.

                    sl=    SGR substring for whole selected  lines  (i.e.,  matching
                           lines when the -v command-line option is omitted, or non-
                           matching lines when -v is  specified).   If  however  the
                           boolean  rv capability and the -v command-line option are
                           both specified, it  applies  to  context  matching  lines
                           instead.   The  default  is  empty  (i.e., the terminal's
                           default color pair).

                    cx=    SGR substring for whole context lines (i.e., non-matching
                           lines  when  the  -v  command-line  option is omitted, or
                           matching lines when -v is  specified).   If  however  the
                           boolean  rv capability and the -v command-line option are
                           both specified, it applies to selected non-matching lines
                           instead.   The  default  is  empty  (i.e., the terminal's
                           default color pair).

                    rv     Boolean value that reverses (swaps) the meanings  of  the
                           sl=  and cx= capabilities when the -v command-line option
                           is specified.  The default is false (i.e., the capability
                           is omitted).

                    mt=01;31
                           SGR substring for matching non-empty text in any matching
                           line (i.e., a selected  line  when  the  -v  command-line
                           option   is  omitted,  or  a  context  line  when  -v  is
                           specified).  Setting this is equivalent to  setting  both
                           ms=  and mc= at once to the same value.  The default is a
                           bold  red  text  foreground   over   the   current   line
                           background.

                    ms=01;31
                           SGR  substring  for matching non-empty text in a selected
                           line.  (This is only used when the -v command-line option
                           is  omitted.)   The  effect  of  the  sl=  (or cx= if rv)
                           capability  remains  active  when  this  kicks  in.   The
                           default  is  a  bold red text foreground over the current
                           line background.

                    mc=01;31
                           SGR substring for matching non-empty text  in  a  context
                           line.  (This is only used when the -v command-line option
                           is specified.)  The effect of the  cx=  (or  sl=  if  rv)
                           capability  remains  active  when  this  kicks  in.   The
                           default is a bold red text foreground  over  the  current
                           line background.

                    fn=35  SGR  substring for file names prefixing any content line.
                           The  default  is  a  magenta  text  foreground  over  the
                           terminal's default background.

                    ln=32  SGR  substring  for  line  numbers  prefixing any content
                           line.  The default is a green text  foreground  over  the
                           terminal's default background.

                    bn=32  SGR  substring  for  byte  offsets  prefixing any content
                           line.  The default is a green text  foreground  over  the
                           terminal's default background.

                    se=36  SGR  substring  for  separators that are inserted between
                           selected line fields (:), between  context  line  fields,
                           (-),  and  between  groups of adjacent lines when nonzero
                           context is specified (--).  The default is  a  cyan  text
                           foreground over the terminal's default background.

                    ne     Boolean  value  that prevents clearing to the end of line
                           using Erase in Line (EL) to Right  (\33[K)  each  time  a
                           colorized  item  ends.   This  is  needed on terminals on
                           which EL is not supported.  It  is  otherwise  useful  on
                           terminals  for  which  the back_color_erase (bce) boolean
                           terminfo capability  does  not  apply,  when  the  chosen
                           highlight colors do not affect the background, or when EL
                           is too slow or causes too much flicker.  The  default  is
                           false (i.e., the capability is omitted).

                    Note  that  boolean  capabilities  have no =...  part.  They are
                    omitted (i.e., false) by default and become true when specified.

                    See   the   Select   Graphic  Rendition  (SGR)  section  in  the
                    documentation of the text terminal that is  used  for  permitted
                    values   and  their  meaning  as  character  attributes.   These
                    substring values are integers in decimal representation and  can
                    be  concatenated with semicolons.  grep takes care of assembling
                    the result into a  complete  SGR  sequence  (\33[...m).   Common
                    values to concatenate include 1 for bold, 4 for underline, 5 for
                    blink, 7 for inverse, 39 for default foreground color, 30 to  37
                    for  foreground  colors,  90  to 97 for 16-color mode foreground
                    colors, 38;5;0 to 38;5;255  for  88-color  and  256-color  modes
                    foreground colors, 49 for default background color, 40 to 47 for
                    background colors, 100  to  107  for  16-color  mode  background
                    colors,  and 48;5;0 to 48;5;255 for 88-color and 256-color modes
                    background colors.

             LC_ALL, LC_COLLATE, LANG
                    These variables specify the locale for the LC_COLLATE  category,
                    which  determines the collating sequence used to interpret range
                    expressions like [a-z].

             LC_ALL, LC_CTYPE, LANG
                    These variables specify the locale for  the  LC_CTYPE  category,
                    which  determines the type of characters, e.g., which characters
                    are whitespace.

             LC_ALL, LC_MESSAGES, LANG
                    These variables specify the locale for the LC_MESSAGES category,
                    which  determines the language that grep uses for messages.  The
                    default C locale uses American English messages.

             POSIXLY_CORRECT
                    If set,  grep  behaves  as  POSIX.2  requires;  otherwise,  grep
                    behaves  more  like  other  GNU programs.  POSIX.2 requires that
                    options that follow file names must be treated as file names; by
                    default,  such  options are permuted to the front of the operand
                    list and are treated as options.  Also,  POSIX.2  requires  that
                    unrecognized  options  be diagnosed as “illegal”, but since they
                    are not really against the law the default is to  diagnose  them
                    as      “invalid”.       POSIXLY_CORRECT      also      disables
                    _N_GNU_nonoption_argv_flags_, described below.

             _N_GNU_nonoption_argv_flags_
                    (Here N is grep's numeric process ID.)  If the ith character  of
                    this  environment variable's value is 1, do not consider the ith
                    operand of grep to be an option, even if it appears to  be  one.
                    A  shell  can  put  this  variable  in  the environment for each
                    command it runs, specifying which operands are  the  results  of
                    file name wildcard expansion and therefore should not be treated
                    as options.  This behavior is available  only  with  the  GNU  C
                    library, and only when POSIXLY_CORRECT is not set.

      EXIT STATUS
             Normally,  the  exit  status  is  0  if  selected lines are found and 1
             otherwise.  But the exit status is 2 if an error occurred,  unless  the
             -q  or --quiet or --silent option is used and a selected line is found.
             Note, however, that POSIX only mandates, for  programs  such  as  grep,
             cmp, and diff, that the exit status in case of error be greater than 1;
             it is therefore advisable, for the sake of portability,  to  use  logic
             that  tests  for  this  general  condition  instead  of strict equality
             with 2.

      COPYRIGHT
             Copyright © 1998, 1999, 2000, 2002, 2005 Free Software Foundation, Inc.

             This is free software; see the source for copying conditions.  There is
             NO warranty; not even for MERCHANTABILITY or FITNESS FOR  A  PARTICULAR
             PURPOSE.

      BUGS
         Reporting Bugs
             Email  bug reports to , a mailing list whose web page
             is .   grep's  Savannah
             bug tracker is located at .

         Known Bugs
             Large  repetition  counts  in the {n,m} construct may cause grep to use
             lots of memory.  In addition, certain other obscure regular expressions
             require  exponential  time  and space, and may cause grep to run out of
             memory.

             Back-references are very slow, and may require exponential time.

      SEE ALSO
         Regular Manual Pages
             awk(1), cmp(1), diff(1), find(1), gzip(1),  perl(1),  sed(1),  sort(1),
             xargs(1),   zgrep(1),   mmap(2),   read(2),   pcre(3),  pcrepattern(3),
             terminfo(5), glob(7), regex(7).

         POSIX Programmer's Manual Page
             grep(1p).

         TeXinfo Documentation
             The full documentation for grep is maintained as a TeXinfo manual.   If
             the  info  and  grep  programs are properly installed at your site, the
             command

                    info grep

             should give you access to the complete manual.

      NOTES
             GNU's not Unix, but Unix is a beast; its plural form is Unixen.



      GNU grep 2.5.1-cvs                2008-02-07                           GREP(1)




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