topic Command Substitution in Operating System - HP-UX

Command Substitution

Raghu Chikkamenahalli — Tue, 25 Nov 2008 13:38:14 GMT

Hi All,

Is nested substitution is possible in shell scripts.
For example
VAR=/home/raghul
VAR1=VAR

And my requirement is, to get the /home/raghul using VAR1 variable.
i.e
If I use ${VAR1} will give VAR and it needs to be get expanded to /home/raghul in one command using echo.

Kindly help if it can be possible.

Thanks,
Regards,
Raghu

Re: Command Substitution

James R. Ferguson — Tue, 25 Nov 2008 13:43:25 GMT

Hi:

Do you mean:

VAR=/home/raghul
# VAR1=${VAR}
# echo $VAR1
/home/raghul

Regards!

...JRF...

Re: Command Substitution

Ivan Krastev — Tue, 25 Nov 2008 13:43:52 GMT

Try this:

VAR=/home/raghul
VAR1=$VAR
echo $VAR1

regards,
ivan

Re: Command Substitution

Raghu Chikkamenahalli — Tue, 25 Nov 2008 16:13:03 GMT

Tried this option VAR1=${VAR1} before this post.
let us say, script check.sh

cat check.sh
------------------------------------------
HOME_PATH="/home/raghul"

VAR=${1}

echo ${VAR}

------------------------------------------
Now If I execute the program
$./check.sh HOME_PATH,
The echo statement should display /home/raghul.
===> ${${VAR}}
===> ${HOME_PATH}
===> /home/raghul
I am extremly sorry if my first question is not clear or deviated from my requirement. The requirement is explained in the second one.

Kindly guide me.

Many Thanks,
Regards,
Raghu.

Re: Command Substitution

James R. Ferguson — Tue, 25 Nov 2008 16:31:11 GMT

Hi (again) Raghu:

Try this:

# cat .check.sh
#!/usr/bin/sh
HOME_PATH="/home/raghul"
VAR=\${$1}
eval echo ${VAR}

# .check.sh HOME_PATH
/home/raghul

Regards!

...JRF...

Re: Command Substitution

Raghu Chikkamenahalli — Tue, 25 Nov 2008 16:52:00 GMT

Hi JRF,

Incredible, Thanks for the solution.

Many Thanks,
Regards,
Raghu.