Can bash show a function's definition?

Question

Is there a way to view a bash function's definition in bash?

For example, say I defined the function foobar

function foobar {
    echo "I'm foobar"
}

Is there any way to later get the code that foobar runs?

$ # non-working pseudocode
$ echo $foobar
echo "I'm foobar"

score 468 · Accepted Answer · edited Dec 04 '18 at 08:52

468

Use type. If foobar is e.g. defined in your ~/.profile:

$ type foobar
foobar is a function
foobar {
    echo "I'm foobar"
}

This does find out what foobar was, and if it was defined as a function it calls declare -f as explained by pmohandras.

To print out just the body of the function (i.e. the code) use sed:

type foobar | sed '1,3d;$d'

edited Dec 04 '18 at 08:52

Coder Guy

answered Aug 02 '11 at 18:43

Benjamin Bannier

2

@sjsupersumit The question explicitly asks for a Bash solution. – bfontaine Sep 05 '18 at 08:59
3

`type` will also expand aliases, which is a nice bonus :) – Esdras Lopez Jun 29 '20 at 01:37
3

this doesn't work for me. It doesn't show the definition of the function, it only shows which file it came from. – gman Sep 02 '21 at 20:40
4

@gman I had the same issue. You are probably using zsh. In that case, `declare -f function_name` will work on both bash and zsh – Aserre Apr 13 '22 at 08:53

score 313 · Answer 2 · answered Aug 02 '11 at 18:41

313

You can display the definition of a function in bash using declare. For example:

declare -f foobar

answered Aug 02 '11 at 18:41

pmohandas

8

Great, to the point, works even when functions defined in other loaded script files. Works also in zsh. – Diego Shevek Oct 26 '17 at 13:44
3

Works with old shells on non-linux systems if you use `typeset -f` – Emmanuel Dec 02 '17 at 19:38
good also that it just shows the `function` definition, so you don't have to parse if that's what you want. – ribamar Mar 07 '18 at 10:04
1

The best answer is on the bottom. It doesn't make sense. – Bijan Aug 11 '20 at 04:56
1

Works also in `zsh`. – TNT Oct 13 '20 at 12:22
This should be the main answer, none of the other worked for me (with .zsh). – petobens Jun 02 '21 at 13:28

score 8 · Answer 3 · answered Jun 29 '16 at 14:29

8

set | sed -n '/^foobar ()/,/^}/p'

This basically prints the lines from your set command starting with the function name foobar () and ending with }

answered Jun 29 '16 at 14:29

2

I'm positively surprised that the `set` output has a) comments stripped out, and b) normalized the white space between function name and parens. I'm still reluctant to use this as there may be variables that contain `}` that may trip the simple parsing. – Robert Jan 05 '21 at 19:12

score 4 · Answer 4 · answered Aug 02 '11 at 18:46

4

set | grep -A999 '^foobar ()' | grep -m1 -B999 '^}'

with foobar being the function name.

answered Aug 02 '11 at 18:46

pyroscope

4

problem: will only display up to the first "}", which is not everything whenever the defintion contains nestings of "{...}" which indeed Bash does allow. – Destiny Architect Jul 21 '14 at 02:45
1

Can also fail if the function contains a here-doc/here-string containing the curly-brace pattern – Cheetah Sep 28 '15 at 16:49

4 Answers4