ShellScript: Not able to run the command using Variable

[psrdotcom]

Hi Folks,

I was trying to form a command using different variables and assigned to one variable including options.

Sample:

CMD="mount"

CMD=$CMD" /dev/sdb"

CMD=$CMD" /mnt/disk0/"

echo "The command is: $CMD"

$CMD

Output:
The command is: mount /dev/sdb /mnt/disk0
Error: No such file or directory:
""

Note: Both the /dev/sdb and /mnt/disk0 exists.

If I am running the same command without using variable from the script, it was working fine.

Please help me to get out of this problem.

[Lars Noodén]

You need to tell it to execute. Try this:

$(echo $CMD)

Vaphell always has good solutions. I hope he sees this thread.

[psrdotcom]

Hi,

Thanks for the reply.

But I have tried that as well. But I am getting error like CMD: command not found

I have put ${CMD}. That also didn't work.

Any other solution plz.

[Lars Noodén]

Yes, but you have to provide the full device name. /dev/sdb is just a start, which partition on /dev/sdb are your trying to mount? /dev/sdb1, /dev/sdb2, etc.?

[psrdotcom]

Hi,

Thanks for the quick reply.

I have put it as an example content.

Actually I was trying different command not the which is mentioned the thread.

I am displaying the command using just before running it.
It was the correct command.
I have copy and paste final command string in script and it was working fine.

What is the problem when I am using with variable.

ex:
echo ${CMD}
${CMD}

Output:
mount /dev/sdb1 /mnt/disk0
File not found error (When executing the command)

If I had placed the same command in script
mount /dev/sdb1 /mnt/disk0
It is executing perfectly.

Please let me know the solution.

[psrdotcom]

Solved it.

I have written the command to a temp file and executed the temp file with in the script.

[bregma]

You're looking for the 'eval' command.

For example,

$ cmd="ls -l"
$ eval $cmd