I am doing some shell scripting.
I use this construction for creating new variables:
eval ${ARG}_ext=fastq
which works pretty nice because then I can use those newly created variable directly like this:
$file_ext
Now I want to assign value to the variable called extension:
extension=
The assigned value should be one found in variable ${ARG}_ext. Please, how can i do that?
I have tried
extension=eval ${ARG}_ext;
but this gives me name of the variable and I want its value. Thanks.
Try:
$ extension=$(eval "echo \$${ARG}_ext")
Not a direct answer, but have you considered using associative arrays instead:
declare -A myhash
ARG=file
myhash[${ARG}_ext]='fastq'
extension="${myhash[${ARG}_ext]}"
echo "$extension"
Note that declare creates a local variable if used inside a function, so declare the associated array in global scope if you need it globally. (The newest versions of bash add a -g (global) option to declare that solves this issue.)
