Since I just learned and used all this stuff today, I think it deserves it's own node.
One of Unix' greatest strengths is it's use if I/O Rediection. You can tell a process where to get data from and where to ship it to all from the command like. Very usefull during debigging a process.
The basic redirection operators are:
- Standard Out (stdout:):
ls -l > file
- Standard In (stdin):
grep condition < file
- Standard Error {stderr}: This deserves special information: Standard in and Stadard error are not the same thing. Redirecting stderr will not redirect stdin and vica-versa.
csh/tcsh: ls non_existent_file* >& file_list
sh/bash:ls -l non_existent_file* file_list 2>&1
There are are some very good nodes on each of these and many others: >> operator, > operator, << operator, < operator