Print n lines of command --help to stdout

Question

It's like a curiosity that I couldn't solve it (try sed, awk, tail, head, etc.).

It works:

$ ls --help | head -n 2
Usage: ls [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).

Why doesn't it work with other teams?

$ tree --help | head -n 2 
Prints the whole --help! not just the first 2 lines!

+3

Yeke 15 Aug 14 at 16:36

1 answer

Mureinik · Accepted Answer · 2014-08-15T16:38:02+0000

tree

(and some other commands) print their help to stderr, not stdout. You can simply redirect both with |&

instead |

:

tree --help |& head -n2