Linux fgrep command

Updated: 05/04/2019 by Computer Hope
fgrep command

On Unix-like operating systems, the fgrep command searches for fixed-character strings in a file or files. "Fixed-character" means the string is interpreted literally — metacharacters do not exist, and therefore regular expressions cannot be used.

This document covers the GNU/Linux version of fgrep.


fgrep is useful when you need to search for strings which contain lots of regular expression metacharacters, such as "$", "^", etc. By specifying that your search string contains fixed characters, you don't need to escape each of them with a backslash.

If your string contains newlines, each line will be considered an individual fixed-character string to be matched in the search.

Running fgrep is the same as running grep with the -F option.


fgrep [-b] [-c] [-h] [-i] [-l] [-n] [-s] [-v] [-x] [ -e pattern_list] 
      [-f pattern-file] [pattern] [file]


-b Precede each line by the block number on which it was found. This can be useful in locating block numbers by context (first block is 0).
-c Print only a count of the lines that contain the pattern.
-h Suppress printing of files when searching multiple files.
-i Ignore upper/lower case distinction during comparisons.
-l Print the names of files with matching lines once, separated by new-lines. Does not repeat the names of files when the pattern is found more than once.
-n Precede each line by its line number in the file (first line is 1).
-s Work silently, that is, display nothing except error messages. This is useful for checking the error status.
-v Print all lines except those that contain the pattern.
-x Print only lines matched entirely.
-e pattern_list Search for a string in pattern-list (useful when the string begins with a "-").
-f pattern-file Take the list of patterns from pattern-file.
pattern Specify a pattern to be used during the search for input.
file A path name of a file to be searched for the patterns. If no file operands are specified, the standard input will be used.


fgrep "support" myfile.txt

Search for "support" in the file myfile.txt.

ed — A simple text editor.
egrep — Filter text which matches an extended regular expression.
grep — Filter text which matches a regular expression.
sed — A utility for filtering and transforming text.
sh — The Bourne shell command interpreter.