I am want to change a global variable (or at least append to it) using a function.
input="Hello"
example=input
func() {
declare -x $example="${input} World"
}
func
echo $input
The output of this would be "Hello" The original value. I would like it if the function were to able to change the original value. Is there alternative to accomplishing this. Please note I need to set example=input and then perform on the operation on example (the variable).
BTW, if I used eval instead the function will complain about World being a function or something.
Did you try using export?
export $example="${input} World"
you should use
declare -x -g $example="${input} World"
in your func
The -g option forces variables to be created or modified at the global scope, even when declare is executed in a shell function. It is ignored in all other cases.
see
http://www.gnu.org/software/bash/manual/bashref.html
Also note in MinGW, it seems that declare does not support the -g option.
You could use eval by redefining func() as the following:
func() {
eval $example=\"${input} World\"
}
This allows the double-quotes to "survive" the first parsing (which expands the variables into their values, as needs to be done) so that eval starts parsing again with the string 'input="Hello World".
As for the use of export to do the job, if the variable input does not actually need to be exported, include its '-n' option:
export -n $example=...
, and the variable remains a shell variable and does not get exported as an environment variable.
