Bash script - run function passed to script

Question

I have a script and am passing a command that I want to then run within the script.

Passing the function like:

bash ./myscript.sh 'yarn test'

I can run the command if I first save it as a variable and then run it like:

FUNC=$1

$FUNC

But can't seem to figure out how to just run it without first saving it.

EDIT:

I should have been more specific with my example, my code more accurately looks like: (using KamilCuk's reply suggestion)

run_command () {
    "$@"
}

run_command

Having the value inside of a function in the script won't run the passed command, having it outside as simply "$@" will run it.

Is there something different I would need to do to have it run within the function?

Why don't you write simply $1 as a command? BTW, you are not passing a function, but the name of a function, which is something different. Functions are not first-class objects in bash, and can't be passed around. — user1934428
– user1934428, Commented Apr 8, 2021 at 13:36
@user1934428 Edited OP to be more clear about what I'm passing. Also have tried simply using $1 and it doesn't run it. — chivs890
– chivs890, Commented Apr 8, 2021 at 13:37
works here I can run the function it's not a function, it's a command. And you should rather prefer passing bash ./myscript.sh yarn test and then do "$@" to properly handle corner cases, like spaces or * characters in arguments. — KamilCuk
– KamilCuk, Commented Apr 8, 2021 at 13:43
Start ./myscript.sh yarn test and run "$@". Otherwise you'll have serious problems when trying to pass arguments with quotes and spaces. Which, now that I read, @KamilCuk already told you. :) — Charles Duffy
– Charles Duffy, Commented Apr 8, 2021 at 13:51
Apologies, I wasn't accurate with my example in the OP. Have updated the example to show that I'm trying to run the passed command within a function in the script. — chivs890
– chivs890, Commented Apr 8, 2021 at 13:52

Mr R · Accepted Answer · 2021-04-08 13:58:18Z

2

Maybe there's something wrong in your script, or yarn can't be found?

Here's an [updated] trivial script and it works ...

#!/bin/sh

run_command() {
    "$@"
}

run_command $@

and when I run it it does run the passed in parameter.

# /var/tmp/myscript.sh "echo Hi"
Hi

You can use the -x option when launching to get a debug trace .. e.g.

# sh -x /var/tmp/myscript.sh "echo Hi"
L-MacBook:TEST rohan$ sh -x /var/tmp/myscript.sh "echo Hi"
+ run_command echo Hi
+ echo Hi
Hi

edited Apr 8, 2021 at 13:58

answered Apr 8, 2021 at 13:45

Mr R

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7 Comments

Charles Duffy Over a year ago

Buggy, though. See BashFAQ #50

chivs890 Over a year ago

Apologies, I wasn't accurate with my example in the OP. Have updated the example to show that I'm trying to run the passed command within a function in the script.

chivs890 Over a year ago

Yes that updated answer works, thank you. Guessing there is therefore no way to run it within the run_command function straight from it being passed in the script? It has to explicitly be passed to that function too?

Mr R Over a year ago

@chivs890 - the "$@" - that's all the args passed to run_command ... each function gets it's own set of $1/$2/etc... so no, not unless your pass or save.

KamilCuk Over a year ago

change run_command $@ to run_command "$@"

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