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 grep(1)                                                             grep(1)




 NAME
      grep, egrep, fgrep - search a file for a pattern

 SYNOPSIS
    Plain call with pattern
      grep [-E|-F] [-c|-l|-q] [-bhinsvwx] pattern [file ...]

    Call with (multiple) -e pattern
      grep [-E|-F] [-c|-l|-q] [-bhinsvwx] -e pattern...  [-e pattern] ...
           [file ...]

    Call with -f file
      grep [-E|-F] [-c|-l|-q] [-bhinsvwx] [-f pattern_file] [file ...]

    Obsolescent:
      egrep [-cefilnsv] [expression] [file ...]

      fgrep [-cefilnsvx] [strings] [file ...]

 DESCRIPTION
      The grep command searches the input text files (standard input
      default) for lines matching a pattern.  Normally, each line found is
      copied to the standard output.  grep supports the Basic Regular
      Expression syntax (see regexp(5)).  The -E option (egrep) supports
      Extended Regular Expression (ERE) syntax (see regexp(5)).  The -F
      option (fgrep) searches for fixed strings using the fast Boyer-Moore
      string searching algorithm.  The -E and -F options treat newlines
      embedded in the pattern as alternation characters.  A null expression
      or string matches every line.

      The forms egrep and fgrep are maintained for backward compatibility.
      The use of the -E and -F options is recommended for portability.

    Options
           -E                  Extended regular expressions.  Each pattern
                               specified is a sequence of one or more EREs.
                               The EREs can be separated by newline
                               characters or given in separate -e expression
                               options.  A pattern matches an input line if
                               any ERE in the sequence matches the contents
                               of the input line without its trailing
                               newline character.  The same functionality is
                               obtained by using egrep.

           -F                  Fixed strings.  Each pattern specified is a
                               sequence of one or more strings.  Strings can
                               be separated by newline characters or given
                               in separate -e expression options.  A pattern
                               matches an input line if the line contains
                               any of the strings in the sequence.  The same
                               functionality is obtained by using fgrep.



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 grep(1)                                                             grep(1)




           -b                  Each line is preceded by the block number on
                               which it was found.  This is useful in
                               locating disk block numbers by context.
                               Block numbers are calculated by dividing by
                               512 the number of bytes that have been read
                               from the file and rounding down the result.

           -c                  Only a count of matching lines is printed.

           -e expression       Same as a simple expression argument, but
                               useful when the expression begins with a
                               hyphen (-).  Multiple -e options can be used
                               to specify multiple patterns; an input line
                               is selected if it matches any of the
                               specified patterns.

           -f pattern_file     The regular expression (grep and grep -E) or
                               strings list (grep -F) is taken from the
                               pattern_file.

           -h                  Suppress printing of filenames when searching
                               multiple files.

           -i                  Ignore uppercase/lowercase distinctions
                               during comparisons.

           -l                  Only the names of files with matching lines
                               are listed (once), separated by newlines.  If
                               standard input is searched, a path name of
                               (standard input) will be written, in the
                               POSIX locale. In other locales, (standard
                               input) may be replaced by something more
                               appropriate in those locales.

           -n                  Each line is preceded by its relative line
                               number in the file starting at 1.  The line
                               number is reset for each file searched.  This
                               option is ignored if -c, -b, -l, or -q is
                               specified.

           -q                  (Quiet) Do not write anything to the standard
                               output, regardless of matching lines.  Exit
                               with zero status upon finding the first
                               matching line.  Overrides any options that
                               would produce output.

           -s                  Error messages produced for nonexistent or
                               unreadable files are suppressed.

           -v                  All lines but those matching are printed.




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 grep(1)                                                             grep(1)




           -w                  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                  (eXact) Matches are recognized only when the
                               entire input line matches the fixed string or
                               regular expression.

      The file name is output in all the cases in which output is generated
      if there are more than one input file, unless the -h option is
      specified.  Care should be taken when using the characters $, *, [, ^,
      |, (, ), and \ in expression, because they are also meaningful to the
      shell.  It is safest to enclose the entire expression argument in
      single quotes ('...').

 EXTERNAL INFLUENCES
    Environment Variables
      LANG determines the locale to use for the locale categories when both
      LC_ALL and the corresponding environment variable (beginning with LC_)
      do not specify a locale.  If LANG is not specified or is set to the
      empty string, a default of C (see lang(5)) is used.

      LC_ALL determines the locale to use to override any values for locale
      categories specified by the settings of LANG or any environment
      variables beginning with LC_.

      LC_COLLATE determines the collating sequence used in evaluating
      regular expressions.

      LC_CTYPE determines the interpretation of text as single byte and/or
      multi-byte characters, the classification of characters as letters,
      the case information for the -i option, and the characters matched by
      character class expressions in regular expressions.

      LC_MESSAGES determines the language in which messages are displayed.

      If any internationalization variable contains an invalid setting, the
      commands behave as if all internationalization variables are set to C.
      See environ(5).

    International Code Set Support
      Single-byte and multi-byte character code sets are supported.

 RETURN VALUE
      Upon completion, grep returns one of the following values:



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 grep(1)                                                             grep(1)




           0    One or more matches found.
           1    No match found.
           2    Syntax error or inaccessible file (even if matches were
                found).

 EXAMPLES
      In the Bourne shell (sh(1)) the following example searches two files,
      finding all lines containing occurrences of any of four strings:

           grep -F 'if
           then
           else
           fi' file1 file2

      Note that the single quotes are necessary to tell grep -F when the
      strings have ended and the file names have begun.

      For the C shell (see csh(1)) the following command can be used:

           grep -F 'if\  then\  else\ fi'  file1  file2

      To search a file named address containing the following entries:

           Ken   112 Warring St.  Apt. A
           Judy  387 Bowditch  Apt. 12
           Ann   429 Sixth St.

      the command:

           grep Judy address

      prints:

           Judy  387 Bowditch  Apt. 12

      To search a file for lines that contain either a Dec or Nov, use
      either of the following commands:

           grep -E '[Dd]ec|[Nn]ov' file
           egrep -i 'dec|nov' file

      Search all files in the current directory for the string xyz:

           grep xyz *

      Search all files in the current directory subtree for the string xyz,
      and ensure that no error occurs due to file name expansion exceeding
      system argument list limits:

           find . -type f -print |xargs grep xyz




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 grep(1)                                                             grep(1)




      The previous example does not print the name of files where string xyz
      appears.  To force grep to print file names, add a second argument to
      the grep command portion of the command line:

           find . -type f -print |xargs grep xyz /dev/null

      In this form, the first file name is that produced by find, and the
      second file name is the null file.

 WARNINGS
      (XPG4 only.) If the -q option is specified, the exit status will be
      zero if an input line is selected, even if an error was detected.
      Otherwise, default actions will be performed.

      If the -w option is specified with non-word constituent characters,
      then the output is unexpected.

 SEE ALSO
      sed(1), sh(1), regcomp(3C), environ(5), lang(5), regexp(5).

 STANDARDS CONFORMANCE
      grep: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2

      egrep: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2

      fgrep: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2




























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