fgrep

fixed-string search without regex

TLDR

Search for literal string

$ fgrep "[search string]" [file.txt]

Search multiple files

$ fgrep "[pattern]" [file1.txt] [file2.txt]

Case insensitive search

$ fgrep -i "[pattern]" [file.txt]

Show line numbers

$ fgrep -n "[pattern]" [file.txt]

Recursive search

$ fgrep -r "[pattern]" [directory]

SYNOPSIS

fgrep [options] pattern [files...]

fgrep searches for fixed strings rather than regular expressions. It's equivalent to grep -F and is faster when searching for literal text without regex metacharacters.The tool treats the pattern as a plain string, so characters like ., *, and [ have no special meaning. This makes it ideal for searching log files, code, or any text containing regex metacharacters.fgrep is particularly useful when the search pattern comes from user input or variables that might contain special characters.

PARAMETERS

PATTERN

Fixed string to search for.

FILES

Files to search.

-i, --ignore-case

Case insensitive matching.

-n, --line-number

Show line numbers.

-r, --recursive

Search directories recursively.

-l, --files-with-matches

Show only filenames.

-c, --count

Count matching lines.

-v, --invert-match

Show non-matching lines.

--help

Display help information.

INSTALL

sudo apt install grep

sudo dnf install grep

sudo pacman -S grep

sudo apk add grep

sudo zypper install grep

brew install grep

CAVEATS

No regex support by design. Deprecated in favor of grep -F; GNU grep 3.8 (2022) and later print a deprecation warning when invoked as fgrep. Multiple patterns require the -f option.

HISTORY

fgrep (fast grep) originated in Unix Version 7 as an optimized grep variant for literal strings. Modern implementations typically link to grep with the -F flag.

RESOURCES

Homepage