Execute stdout results

Question

Is there a way to actually execute results from a shell command, instead of using them as arguments to another command?

For instance, I'd like to run '--version' on all executables in a folder, something like:

ls /usr/bin/ | --version

I've found a way using find/exec:

find /usr/ -name valgrind -exec {} --version \;

But I'd like to do it with ls. I've search for over 45 minutes and can't find any help.

score 2 · Accepted Answer · edited Oct 24 '16 at 00:07

2

Try doing this :

printf '%s\n' /usr/bin/* | while IFS= read -r cmd; do "$cmd" --version; done

edited Oct 24 '16 at 00:07

Gilles 'SO- stop being evil'

829,060

answered Oct 23 '16 at 21:40

Gilles Quénot

33,867

I'm getting a permission denied error, even when I run it as root :( – Jex_and_Izzy Oct 23 '16 at 23:00
@Jex_and_Izzy Then you have a file in /usr/bin that isn't executable, or that is a directory. – Gilles 'SO- stop being evil' Oct 24 '16 at 00:07
You are right Gilles, was wrong on my end. Thanks – Jex_and_Izzy Oct 24 '16 at 15:44
1

This is not using ls as requested. – user1133275 Oct 24 '16 at 17:32
@user1133275 and that is a good thing. Granted, probably won't be an issue in /usr/bin but you never know and, in any case, ls isn't the right too for the job. – terdon Dec 08 '16 at 23:38

score 2 · Answer 2 · answered Oct 23 '16 at 23:12

2

If you're trying to execute every executable file in a certain directory with a --version option, try this one-liner (using /usr/bin as the example directory):

for f in /usr/bin/*; do [ -x "$f" ] && $f --version; done

answered Oct 23 '16 at 23:12

Jeff Schaller

67,283
35
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This worked also. Thank you. I'd up-vote it but I don't have enough rep points :( – Jex_and_Izzy Oct 24 '16 at 16:11

user1133275 · Answer 3 · 2016-10-24T01:59:24.140

1

perl and bash;

ls -1 | perl -pe 's/\n/ --version;\n/g' | bash

or xargs;

ls -1 | xargs -I {} bash {} --version;

edited Oct 24 '16 at 01:59

answered Oct 23 '16 at 21:37

user1133275

5,574

$ ls -1 | xargs -I{} {} --version output is : xargs: {}: No such file or directory – Gilles Quénot Oct 23 '16 at 21:39
No, same thing hapenned – Gilles Quénot Oct 23 '16 at 21:41
The first suggestion works, although I receive a "bash: line 2: --version: command not found" error after each output – Jex_and_Izzy Oct 23 '16 at 23:02
@user1133275 First works, second still doesn't – Jex_and_Izzy Oct 24 '16 at 16:17
@Jex_and_Izzy I'd need a more specific example to reproduce and correct the issue you are having with the second one. – user1133275 Oct 24 '16 at 17:32
@user1133275 I have a test folder which contains a 'make' executable and a 'valgrind' executable. When I run the second command, the output is:
make-4.2.1: make-4.2.1: cannot execute binary file valgrind: valgrind: cannot execute binary file
– Jex_and_Izzy Oct 26 '16 at 20:20

score 0 · Answer 4 · answered Oct 24 '16 at 02:07

0

to reevaluate shell output as shell input, use eval.

eval "$(your command here)"

answered Oct 24 '16 at 02:07

mikeserv

58,310

1

We should note that eval must be used with care, at least sanity check the eval input first (And welcome back @mikeserv). – cuonglm Oct 24 '16 at 02:14
@cuonglm - just stopping by. I have less time even than before for this stuff lately. I've been homeless since my house burnt down last month – mikeserv Oct 24 '16 at 10:03
2

Ops, I'm sorry about that, hope you will be better soon. – cuonglm Oct 24 '16 at 11:50

Execute stdout results

4 Answers4