I use zsh at the command-line but the shell scripts I write run bash so that they are portable.
I was learning about IO redirection from here when I realized this difference:
Note that the command is just an arbitrary one whose first line of output is over stderr and the second line comes over stdout.
zsh on OS X:
% ls -ld /tmp /tnt 1>&2 2>&1 | sed -e 's/^/++/'
ls: /tnt: No such file or directory
++ls: /tnt: No such file or directory
lrwxr-xr-x@ 1 root wheel 11 Oct 19 2012 /tmp -> private/tmp
++lrwxr-xr-x@ 1 root wheel 11 Oct 19 2012 /tmp -> private/tmp
bash:
bash-3.2$ ls -ld /tmp /tnt 1>&2 2>&1 | sed -e 's/^/++/'
ls: /tnt: No such file or directory
lrwxr-xr-x@ 1 root wheel 11 Oct 19 2012 /tmp -> private/tmp
I'm having a hard time figuring out zsh's output.
Also, on a Linux the output order's slightly different for zsh:
% ls -ld /tmp /tnt 1>&2 2>&1 | sed -e 's/^/++/'
ls: cannot access /tnt: No such file or directory
drwxrwxrwt. 13 root root 4096 Dec 19 23:11 /tmp
++ls: cannot access /tnt: No such file or directory
++drwxrwxrwt. 13 root root 4096 Dec 19 23:11 /tmp
bash output is identical though.
More experimentation in zsh:
% ls -ld /tmp /tnt 1>&2 | sed -e 's/^/++/'
ls: /tnt: No such file or directory
lrwxr-xr-x@ 1 root wheel 11 Oct 19 2012 /tmp -> private/tmp
++lrwxr-xr-x@ 1 root wheel 11 Oct 19 2012 /tmp -> private/tmp
% ls -ld /tmp /tnt 2>&1 | sed -e 's/^/++/'
++ls: /tnt: No such file or directory
++lrwxr-xr-x@ 1 root wheel 11 Oct 19 2012 /tmp -> private/tmp
That last one there produces identical results to bash.
I figure I should prefer learning bash's behavior inside-out before delving into how zsh ticks, but this isn't really ideal because chances are at least half of the IO redirection I expect to be doing will be spur-of-the-moment hacks that I surely will want to try from the zsh prompt. And I'm actually pretty invested in zsh because I have a ton of custom plugins and it would be a major effort at this point to do a big switch back to bash.
