stdin, stdout, stderr and redirection

gistfile1.txt

0 = stdin
1 = stdout
2 = stderr

#redirects stdout from command to file
command > file

#equivalent to
command 1> file

#if command writes errors to stderr, redirecting only stdout doesn't capture the errors
#this redirects stderr to errors.txt, stdout is left unchanged
command 2> errors.txt

#redirects stdout from command to file and then redirects stderr to current redirection for stdout (also to the file)
#note that this order is important
command > file 2>&1