I have the following:
#!/bin/sh
n=('fred' 'bob')
f='n'
echo ${${f}[@]}
and I need that bottom line after substitutions to execute
echo ${n[@]}
any way to do this? I just get
test.sh: line 8: ${${f}}: bad substitution
on my end.
Add a comment
|
2 Answers
You can do variable indirection with arrays like this:
subst="$f[@]"
echo "${!subst}"
As soulmerge notes, you shouldn't use #!/bin/sh for this. I use #!/usr/bin/env bash as my shebang, which should work regardless of where Bash is in your path.
1 Comment
Gordon Davisson
+1 Indirect expansion is far less of a bug magnet than
eval.You could eval the required line:
eval "echo \${${f}[@]}"
BTW: Your first line should be #!/bin/bash, you're using bash-specific stuff like arrays
3 Comments
jman
+1 if I had any votes remaining today. Can you explain what eval does?
soulmerge
I do not understand why people keep downvoting without providing any feedback?
Michael Hoffman
I didn't downvote, but in general things like
eval should be avoided in most languages if there is an alternative. They sometimes introduce subtle bugs or security risks.