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Asked: 2026-05-23T15:42:20+00:00

I would like to execute two or more commands back to back . But

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I would like to execute two or more commands back to back . But these commands are stored in a variable in my script. For example,

var="/usr/bin/ls ; pwd ; pooladm -d; pooladm -e"

The problem arises when I execute this variable via my script.
Suppose I go:

#!/bin/ksh -p
..
..
var="/usr/bin/ls ; pwd;pooladm -d; pooladm -e"
..
..
$var # DOES NOT WORK ..BUT WORKS WITH EVAL

It doesn’t work ..
But the moment I use eval :

eval $var

It works brilliantly.

I was just wondering if there is any other way to execute a bunch of commands stored in a variable without using eval.

Also , Is eval usage considered a bad programming practice because my coding standards appear to shun its usage than embrace it . Please do let me know.

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1 Answer

  1. Editorial Team

    Remember that the shell only parses the line once. So when you expand your $var, it becomes one string containing blanks. Since you have no executable named ‘/usr/bin/ls ; pwd;pooladm -d; pooladm -e’, it can’t run it.

    On the other hand, eval takes its arguments are re-scans them, now you get ‘/usr/bin/ls’, ‘pwd’, and so on. It works.

    eval is a little chancy because it leaves a possible security hole — consider if someone managed to get ‘rm -rf /’ into the string. But it’s a useful tool.

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