Comments on: Writing Functions in Shell Script

By: spacebat

spacebat — Fri, 10 Jul 2009 10:59:14 +0000

My method suffers from increased need for quoting (say the parameters have spaces, you might need to quote them and escape the quotes before passing to eval), also it won’t work if the variable name you pass in is the same name as the local variable used to store the name, ie this is broken:

myfunc var “holly” “wood”

I’ve never run into that problem in real life, but I’ve been reading about it in the context of lisp macros where its known as variable capture. A workaround would be to prefix local vars with underscores.
Anyway at this point I tend to think heck this needs porting to perl or python :)

By: Viral Patel

Viral Patel — Fri, 10 Jul 2009 10:33:27 +0000

Hi spacebat.. I resolved the backslash issue. Thanks for the code.

By: spacebat

spacebat — Fri, 10 Jul 2009 10:23:53 +0000

Damn, it backslashed all the quotes and backslashes :\

By: spacebat

spacebat — Fri, 10 Jul 2009 10:22:30 +0000

Capturing echoed output is fairly useful, but then obtaining the success or failure of the function can get tricky. I might write it like this:

myfunc() {
local var=$1
eval $var="$2$3"
}

This makes it handy to test the return value of a function that might fail:
if myfunc value "holly" "wood"; then
echo "$value beckons!"
else
echo woe is me
fi