Module 52 fgrep | Illustrated Unix System V/Bsd

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Module 52
fgrep

DESCRIPTION

The external fgrep command is used to search ASCII text files for a specific character string. Any lines containing the string are written to the standard output. The pattern may be a word or string of characters . Regular expressions are not supported by the fgrep command. fgrep is designed to be a fast, simple form of the grep command. If fgrep searches more than one file, each displayed line is preceded by the filename. If no filenames are given, fgrep reads from the standard input. Thus you can use fgrep in a pipe command.

The name fgrep is a combination of editor command characters. It is from the editor command :g/RE/p, which translates to global Regular Expression print. The f stands for fast. Thus fgrep is fast global RE print. Unfortunately, this is a misnomer because fgrep cannot search for Regular Expression patterns.

NOTE:
The fgrep command performs line oriented searches. Therefore, a phrase that spans more than one line is not matched. Thus when deciding what string to use for the search, you should try to keep it as short as possible yet as unique as possible.

COMMAND FORMAT

Following is the general format of the fgrep command.

 fgrep [ -bchilnvx ] [ -e -string ] string file_list      fgrep [ -bchilnvx ] [ -e -string ] -f file file_list

BSD (Berkeley)

	`fgrep [ -bcilnvx ] [ -e -string ] string file_list`
	`fgrep [ -bcilnvx ] [ -e -string ] -f file file_list`

The first form of the command uses the string provided on the command line to search the file_list for a match. In the second form, multiple strings are stored in file and fgrep searches the file_list for each string listed.

Options

The following list describes the options and their arguments that may be used to control how fgrep functions.

-b	Displays the block number in which the pattern was found before the line that contains the matching pattern .
-c	Displays only a total count of matching lines for each file processed .
-e -string	The string begins with a dash. This allows you to specify a string that begins with a dash. Normally, any argument beginning with a dash is interpreted as an option, not a string or argument.
-f file	Read in the strings to search for from file . This allows you to create a file containing all of the strings you want fgrep to search for in the file_list or standard input.
-h	Suppress the displaying of filenames which precede lines that match the specified patterns when multiple files are searched.
-i	Ignore the difference between uppercase and lowercase characters during comparisons.
-l	Displays only the names of the files containing the specified pattern . The lines containing the patterns are not displayed.
-n	Displays the line number before each line containing the pattern .
-v	Displays only the lines that do not match the pattern . The v command in the ex editor performs the same type of function. It is an exception search. Search for every line except the ones containing the given pattern .
-x	Displays only those lines matched in their entirety.

Arguments

The following list describes the arguments that may be passed to the fgrep command.

string	Any combination of characters that are literally interpreted by fgrep as strings to search for in the given input stream of data
file_list	One or more files to search for the given pattern

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