Output redirection, pipe and ``

Question

I am trying to pass result of which env to nano by this command nano < which env, but it seems, that I didn't understand the whole concept.

When I execute this I assume that: which env STDOUT will go to the nano STDIN. So this will equal to nano /some/path. But, apparently, I am wrong.

Also I tried which env | nano with same purpose, but output was:

Received SIGHUP or SIGTERM

Can somebody clarify this?

then your nano version is older (must be >=2.2 for stdin feature, you can check with nano -V ). then workarround would be: `nano <(which env)` — MetNP, Nov 29 '16 at 17:41
I'm assuming that `env` in your system is something editable by nano (it's a 64-bit Mach executable on mine, so I don't really want to risk corrupting it), so I substituted the `cd` command and `nano $(which cd)` does what you are expecting, at least on OSX. — Thomas N, Nov 29 '16 at 17:44
@ThomasN @MetNP Yes, also I can `nano `which env``, but also I hoped for a little bit more detailed answer with explanation how it works and why my solution does not. — IgorNikolaev, Nov 29 '16 at 17:48

score 1 · Answer 1 · edited Apr 13 '17 at 12:36

nano, like most text editors, expects a file name to edit as its command-line argument, not as standard input.

$ which env | nano    # pass as standard input, does not work
$ nano "$(which env)" # pass as command-line argument, works

So it's not working because that's not how nano expects to be used.

With some editors (apparently not your version of nano), you can use:

$ which env | some-other-editor -  # note hyphen as file name

to edit standard input as text (you'd be editing a document with the string "/usr/bin/env", not the program /usr/bin/env itself).

Also, if you want to change delimited names on standard input into arguments, xargs will do that for you.

PS: which doesn't always do what you want, consider command -v instead. For details, see Why not use "which"? What to use then?

Output redirection, pipe and ``

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