grep is one of the most useful commands to learn. It allows you find data inside of data.The syntax of the command is grep <string> <file> however file is optional if you're using piping.

Note: You can search multiple files at the same time, meaning you can theoretically do

grep <string> <file> <file2>

For instance let's say you know have the file name of test1234, but you don't know where it is on the system. find can be used to list every file on the OS, and grep can be used to find the actual file.

What about if you have a bunch of data, and you wanna see if the string hello is in it, and if so what line number it's at.

Note: grep supports regular expressions, the syntax is actually

grep <regular expression> <file>