[SOLVED] What is the equivalent of this bash script in sh script?

archieval · 10-05-2010, 01:38 AM

Below is a script for dynamic variable creation

Code:

#!/bin/bash

variableName="test"
variableVal="123"
eval ${variableName}=`echo -ne \""${variableVal}"\"`

echo $test #"test" variable created dynamically using eval

When I execute this with the first line set to #!/bin/sh, the result is
eval: 1: 123: not found

But when I execute it as is above noting #!/bin/bash, it works as desired and the result is
123

I am wondering what is the difference, and what is the equivalent of this script if it is written in sh.

Thanks!

Regards,
archieval

grail · 10-05-2010, 02:11 AM

Out of curiosity, have you changed the name to something other than 'test' which in itself is a command that eval may have evaluated?

colucix · 10-05-2010, 02:30 AM

The problem is that the echo built-in in the Bourne Shell does not accept options, so that the command substitution results in a literal

Code:

-ne "123"

hence the error from eval, which tries to evaluate the expression:

Code:

test=-ne "123"

You can either remove -ne from the echo call or simplify you script using a simple variable substitution (actually I don't see any utility for the echo statament in this case):

Code:

eval ${variableName}=${variableVal}

Hope this helps.

archieval · 10-05-2010, 03:09 AM

Ah so that's the reason for the error. I just copied that script from a certain website, not knowing that it can be simplified because I do not know the meaning of "echo -ne xxx", so I execute it as is. Hey this really helps and a new knowledge! Thanks!

Regards,
archieval