CODEWITHSUNDEEP
sh
Brian
Brian

Reputation: 1989

How to pipe into grep using backticks in Linux shell script?

I am trying to execute, what I thought would be, a simple shell command within a script. When I execute this from the command prompt, it works well:

$ sudo cat /etc/sysconfig/network-scripts/ifcfg-en0 | grep "IPADDR"
IPADDR=192.168.1.10

However, if I put this into a shell script:

#!/usr/bin/sh
my_command=`sudo cat /etc/sysconfig/network-scripts/ifcfg-en0 | grep "IPADDR"`
${my_command}
echo $?

I get this error:

$ sudo ./myscript.sh
./myscript.sh: line 3: IPADDR=192.168.1.10: command not found

So, how can I successfully execute this line within my shell script?

Thanks!

Upvotes: 0

Views: 219

Answers (1)

Flash Thunder
Flash Thunder

Reputation: 12036

The problem in your case is that you are executing the result of the command...

This line executes the code as it's between "``" that are special characters for executing the given string as a command:

my_command=`sudo cat /etc/sysconfig/network-scripts/ifcfg-en0 | grep "IPADDR"`

as a result, $my_command is "IPADDR=192.168.1.10"

Then you are trying to execute it for the second time:

${my_command}

Thats why you are getting this error. There is no such a command as "IPADDR=192.168.1.10".

Just use $my_command as a result that contains your desired grepped part and skip the ${my_command} line:

#!/usr/bin/sh
my_command=`sudo cat /etc/sysconfig/network-scripts/ifcfg-en0 | grep "IPADDR"`
echo $my_command

Upvotes: 1

Related Questions