Listing defined functions in bash

Question

I'm trying to write some code in bash which uses introspection to select the appropriate function to call.

Determining the candidates requires knowing which functions are defined. It's easy to list defined variables in bash using only parameter expansion:

$ prefix_foo="one"
$ prefix_bar="two"
$ echo "${!prefix_*}"
prefix_bar prefix_foo

However, doing this for functions appears to require filtering the output of set -- a much more haphazard approach.

Is there a Right Way?

Answer 1

One (ugly) approach is to grep through the output of set:

set \
  | egrep '^[^[:space:]]+ [(][)][[:space:]]*$' \
  | sed -r -e 's/ [(][)][[:space:]]*$//'

Better approaches would be welcome.

Answer 2

Use the declare builtin to list currently defined functions:

declare -F

Answer 3

I have an entry in my .bashrc that says:

alias list='declare -F |cut -d" " -f3'

Which allows me to type list and get a list of functions. When I added it, I probably understood what was happening, but I can't remember to save my life at the moment.

Good luck,

--jed

Answer 4

$ declare -F
declare -f ::
declare -f _get_longopts
declare -f _longopts_func
declare -f _onexit
...

So, Jed Daniel's alias,

declare -F | cut -d" " -f3

cuts on a space and echos the 3rd field:

$ declare -F | cut -d" " -f3
::
_get_longopts
_longopts_func
_onexit

Answer 5

Pure Bash:

saveIFS="$IFS"
IFS=$'\n'
funcs=($(declare -F))      # create an array
IFS="$saveIFS"
funcs=(${funcs[@]##* })    # keep only what's after the last space

Then, run at the Bash prompt as an example displaying bash-completion functions:

$ for i in ${funcs[@]}; do echo "$i"; done
__ack_filedir
__gvfs_multiple_uris
_a2dismod
. . .
$ echo ${funcs[42]}
_command

Answer 6

How about:

compgen -A function   # compgen is a shell builtin

Answer 7

Perhaps my solution for this thread will work for you. Google for "get a list of function names in a shell script site:stackoverflow.com"

http://stackoverflow.com/questions/2630812/get-a-list-of-function-names-in-a-shell-script