4.3BSD - /usr/man/cat1/grep.0

GREP(1)                                                                GREP(1)


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

SYNOPSIS
       grep [ option ] ...  expression [ file ] ...

       egrep [ option ] ...  [ expression ] [ file ] ...

       fgrep [ option ] ...  [ strings ] [ file ]

DESCRIPTION
       Commands  of  the  grep  family  search the input files (standard input
       default) for lines matching a pattern.  Normally, each  line  found  is
       copied  to  the  standard  output.   Grep  patterns are limited regular
       expressions in the style of ex(1); it uses a  compact  nondeterministic
       algorithm.  Egrep patterns are full regular expressions; it uses a fast
       deterministic algorithm that sometimes needs exponential space.   Fgrep
       patterns  are  fixed  strings;  it  is fast and compact.  The following
       options are recognized.

       -v     All lines but those matching are printed.

       -x     (Exact) only lines matched in their entirety are printed  (fgrep
              only).

       -c     Only a count of matching lines is printed.

       -l     The  names  of files with matching lines are listed (once) sepa‐
              rated by newlines.

       -n     Each line is preceded by its relative line number in the file.

       -b     Each line is preceded by the block number on which it was found.
              This  is sometimes useful in locating disk block numbers by con‐
              text.

       -i     The case of letters is ignored in making comparisons — that  is,
              upper  and lower case are considered identical.  This applies to
              grep and fgrep only.

       -s     Silent mode.  Nothing is printed (except error messages).   This
              is useful for checking the error status.

       -w     The  expression  is  searched for as a word (as if surrounded by
              ‘\<’ and ‘\>’, see ex(1).)  (grep only)

       -e expression
              Same as a  simple  expression  argument,  but  useful  when  the
              expression begins with a -.

       -f file
              The  regular  expression (egrep) or string list (fgrep) is taken
              from the file.

       In all cases the file name is shown if there is  more  than  one  input
       file.  Care should be taken when using the characters $ * [ ^ | ( ) and
       \ in the expression as they are also meaningful to the  Shell.   It  is
       safest  to enclose the entire expression argument in single quotes �´ �´.

       Fgrep searches for lines that contain one  of  the  (newline-separated)
       strings.

       Egrep  accepts extended regular expressions.  In the following descrip‐
       tion ‘character’ excludes newline:

              A \ followed by a single character other  than  newline  matches
              that character.

              The character ^ matches the beginning of a line.

              The character $ matches the end of a line.

              A .  (period) matches any character.

              A  single  character  not otherwise endowed with special meaning
              matches that character.

              A string enclosed in brackets [] matches  any  single  character
              from  the string.  Ranges of ASCII character codes may be abbre‐
              viated as in ‘a-z0-9’.  A ] may occur only as the first  charac‐
              ter of the string.  A literal - must be placed where it can’t be
              mistaken as a range indicator.

              A regular expression followed  by  an  *  (asterisk)  matches  a
              sequence of 0 or more matches of the regular expression.  A reg‐
              ular expression followed by a + (plus) matches a sequence  of  1
              or more matches of the regular expression.  A regular expression
              followed by a ? (question mark) matches a sequence  of  0  or  1
              matches of the regular expression.

              Two  regular expressions concatenated match a match of the first
              followed by a match of the second.

              Two regular expressions separated by | or newline match either a
              match for the first or a match for the second.

              A regular expression enclosed in parentheses matches a match for
              the regular expression.

       The order of precedence of operators at the same parenthesis  level  is
       [] then *+? then concatenation then | and newline.

       Ideally there should be only one grep, but we don’t know a single algo‐
       rithm that spans a wide enough range of space-time tradeoffs.

SEE ALSO
       ex(1), sed(1), sh(1)

DIAGNOSTICS
       Exit status is 0 if any matches are found, 1  if  none,  2  for  syntax
       errors or inaccessible files.

BUGS
       Lines are limited to 256 characters; longer lines are truncated.


4th Berkeley Distribution       April 29, 1985                         GREP(1)