Linux Pocket Guide

Input/output redirection

The shell can redirect standard input, standard output, and standard error to and from files. In other words, any command that reads from standard input can have its input come from a file instead with the shell’s < operator:

$ mycommand < infile

Likewise, any command that writes to standard output can write to a file instead:

$ mycommand > outfile                Create/overwrite outfile
$ mycommand >> outfile               Append to outfile

A command that writes to standard error can have its output redirected to a file as well:

$ mycommand 2> errorfile

To redirect both standard output and standard error to files:

$ mycommand > outfile 2> errorfile    Separate files
$ mycommand > outfile 2>&1            Single file