grep

[vinhnx]

NAME
       grep, egrep, fgrep, rgrep - print lines matching a pattern

SYNOPSIS
       grep [OPTIONS] PATTERN [FILE...]
       grep [OPTIONS] [-e PATTERN | -f FILE] [FILE...]

DESCRIPTION
       grep  searches the named input FILEs (or standard input if no files are
       named, or if a single hyphen-minus (-) is given as file name) for lines
       containing  a  match to the given PATTERN.  By default, grep prints the
       matching lines.

       In  addition,  three  variant  programs  egrep,  fgrep  and  rgrep  are
       available.   egrep  is  the  same  as  grep -E.   fgrep  is the same as
       grep -F.  rgrep is the same as grep -r.  Direct  invocation  as  either
       egrep  or  fgrep  is  deprecated,  but  is provided to allow historical
       applications that rely on them to run unmodified.

Usage:

$ cd myDir
$ grep -nr "foo" .

where

-n, --line-number
              Prefix  each  line of output with the 1-based line number within
              its input file.  (-n is specified by POSIX.)

-R, -r, --recursive
              Read all  files  under  each  directory,  recursively;  this  is
              equivalent to the -d recurse option.

IMPORTANT NOTE: notice the . at the end, it's for directory option, here we pass . to indicate this, or myDir.

Reference:

• grep man: http://linuxcommand.org/lc3_man_pages/grep1.html
• https://stackoverflow.com/questions/4121803/how-can-i-use-grep-to-find-a-word-inside-a-folder

[vinhnx]

Shameless plug, check out perg, my own lightweight grep implementation written in Rust. 🦀

https://github.com/vinhnx/perg