egrep

Search for pattern in file

$ egrep "[pattern]" [file.txt]

$ egrep -i "[pattern]" [file.txt]

$ egrep -n "[pattern]" [file.txt]

$ egrep -r "[pattern]" [directory]

$ egrep "[pattern1|pattern2]" [file.txt]

$ egrep -c "[pattern]" [file.txt]

$ egrep -l "[pattern]" [*.txt]

egrep [options] pattern [file...]

egrep searches files for lines matching an extended regular expression pattern. It's equivalent to `grep -E` and supports ERE syntax including +, ?, |, and () without escaping.
Extended regular expressions are more readable than basic grep patterns for complex matches. Alternation (|), grouping (), and quantifiers work directly without backslashes.
egrep is deprecated in favor of `grep -E` but remains widely available for compatibility.

PATTERN

Extended regular expression.

File(s) to search.

Case-insensitive search.

Show line numbers.

Recursive search.

Show only filenames.

Count matching lines.

Invert match (non-matching lines).

Show only matched parts.

Display help information.

Deprecated - use grep -E. Behavior may vary between implementations. Large files may be slow. Binary files may produce garbage output.

egrep was originally a separate program with extended regex support. Modern grep includes this functionality with the -E flag, making standalone egrep redundant but preserved for compatibility.

grep(1), fgrep(1), sed(1), awk(1)