grep - search a file for a pattern

grep [-E| -F][-c| -l| -q][-insvx] -e pattern_list... [-f pattern_file]...[file...]

grep [-E| -F][-c| -l| -q][-insvx][-e pattern_list]... -f pattern_file...[file...]

grep [-E| -F][-c| -l| -q][-insvx] pattern_list[file...]

The grep utility searches the input files, selecting lines matching one or more patterns; the types of patterns are controlled by the options specified. The patterns are specified by the -e or -f optiont, or the pattern_list operand. The pattern_list's value shall consist of one pattern; the pattern_file's contents shall consist of one or more
patterns terminated by <newline>. An input line shall be selected if any pattern, treated as a Lua pattern, matches any part of the line excluding the terminating <newline>; a null pattern shall match every line. By default, each selected input line shall be written to the standard output.

Regular expression matching shall be based on text lines. Since a <newline> separates or terminates patterns (see the -e and -f options below), regular expressions cannot contain a <newline>. Similarly, since patterns are matched against individual lines (excluding the terminating <newline>s) of the input, there is no way for a pattern to match a <newline> found in the input.

• -F

  Match using fixed strings. Treats each pattern specified as a string instead of a regular expression.

• -c

  Write only a count of selected lines to standard output.

• -e pattern

  Specify one pattern to be used during the search fot input. Unless the -F option is also specified, each pattern is treated as a Lua pattern. Multiple -e or -f options are accepted.

• -f pattern_file

  Read one or more patterns to be used during the search fo input. The patterns in pattern_file should be terminated by a <newline>. Unless the -F option is also specified, each pattern is treated as a Lua pattern.

• -i

  Perform pattern matching in searches without regard of case.

• -l (the letter ell.)

  Write only the names of files containing selected lines to standard output. Pathnames shall be written once per file searched.

• -n

  Preced each output line by its relative line number in each file, each file starting at line 1.

• -q

  Quiet. Nothing is written to the standard output, regardless of mathcing lines.

• -s

  Suppress the error messages ordinarly written for nonexistent or unreadable files. Other error messages will not be suppressed.

• -v

  Select lines not matching any of the specified patterns.

• -x

  Consider only inptu lines that use all characters in the line excluding the terminating to match an entire fixed string or regular expression to be matching lines.

• grep -n local file.lua

  Look for the word local in the file file.lua and print line numbers

• grep -F % file

  Look for the string % in file.

• grep -n -e local -e (.-)=(.-) file.lua

  Look for variable declarations and assignments in the file file.lua and print line numbers