fgrep

Search for literal string

$ fgrep "[search string]" [file.txt]

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

$ fgrep -i "[pattern]" [file.txt]

$ fgrep -n "[pattern]" [file.txt]

$ fgrep -r "[pattern]" [directory]

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.

PATTERN

Fixed string to search for.

Files to search.

Case insensitive matching.

Show line numbers.

Search directories recursively.

Show only filenames.

Count matching lines.

Show non-matching lines.

Display help information.

No regex support by design. Deprecated in favor of grep -F. Multiple patterns require -f option.

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.

grep(1), egrep(1), rg(1)