grep

Find patterns in files using regular expressions. More information: https://www.gnu.org/software/grep/manual/grep.html.

• Search for a pattern within a file:

grep "search_pattern" path/to/file

• Search for an exact string (disables regular expressions):

grep -F|--fixed-strings "exact_string" path/to/file

• Search for a pattern in all files recursively in a directory, showing line numbers of matches, ignoring binary files:

grep -r|--recursive -n|--line-number --binary-files without-match "search_pattern" path/to/directory

• Use extended regular expressions (supports ?, +, {}, () and |), in case-insensitive mode:

grep -E|--extended-regexp -i|--ignore-case "search_pattern" path/to/file

• Print 3 lines of context around, before, or after each match:

grep --context|before-context|after-context 3 "search_pattern" path/to/file

• Print file name and line number for each match with color output:

grep -H|--with-filename -n|--line-number --color=always "search_pattern" path/to/file

• Search for lines matching a pattern, printing only the matched text:

grep -o|--only-matching "search_pattern" path/to/file

• Search stdin for lines that do not match a pattern:

cat path/to/file | grep -v|--invert-match "search_pattern"