Not able to store command inside a shell variable, and run the variable


 
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# 1  
Old 11-19-2010
Not able to store command inside a shell variable, and run the variable

Hi,

I am trying to do the following thing

Code:
var='date'
 
$var

Above command substitutes date for and in turn runs the date command and i am getting the todays date value.

I am trying to do the same thing as following, but facing some problems,

Code:
unique_host_pro="sed -e ' /#/d' \$configFile | awk -v appcode=\"$appcode\" -F\"\$config_del\" '{ if (\$1 == appcode ) print \$0 }' | awk -v unique_host=\"\$unique_host\" -F\"\$config_del\" '{ if ( \$2 == unique_host ) print \$0 }'"

I have stored the sed command in unique_host_pro variable and going to use the variable in multiple places of my script, so i dont have to use the command in multiple places, and also trying to avoid updates to the command in multiple places.

once assigning the above value, i am trying to run the command using

Code:
$unique_host_pro

Getting the following exception

Code:
checkProcess.sh: line 97: sed -e ' /#/d' $configFile | awk -v appcode="$appcode" -F"$config_del" '{ if ($1 == appcode ) print $0 }' | awk -v unique_host="$unique_host" -F"$config_del" '{ if ( $2 == unique_host ) print $0 }': No such file or directory


Please let me know how to correct this error also let me know if the approach is correct.

Last edited by radoulov; 11-19-2010 at 06:07 AM.. Reason: Use code tags, please!
# 2  
Old 11-19-2010
In order to reuse an existing code you should use a shell function.
You get the above error because the shell tries to execute the saved pipeline as a single command.
# 3  
Old 11-19-2010
Thanks, So do you mean that pipline command should not be stored and reused ?

My code is like following

Code:
function checkProcessIdeHosts()
{
 unique_host=$1
 
 no_unique_hosts_prc=`sed -e ' /#/d' $configFile | awk -v appcode="$appcode" -F"$config_del" '{ if ($1 == appcode ) print $0 }' | awk -v unique_host="$unique_host" -F"$config_del" '{ if ( $2 == unique_host ) print $0 }'|wc -l`
 if [ $no_unique_hosts_prc -eq 1 ]
 then 
  checkProcessModule `sed -e ' /#/d' $configFile | awk -v appcode="$appcode" -F"$config_del" '{ if ($1 == appcode ) print $0 }'| awk -v unique_host="$unique_host" -F"$config_del" '{ if ( $2 == unique_host ) print $0 }'`
 else
  for proc_det in `sed -e ' /#/d' $configFile | awk -v appcode="$appcode" -F"$config_del" '{ if ($1 == appcode ) print $0 }'| awk -v unique_host="$unique_host" -F"$config_del" '{ if ( $2 == unique_host ) print $0 }'`
  do
          checkProcessModule $proc_det 
   sleep 5
  done
 fi
}

I am using the command "sed -e ' /#/d' $configFile | awk -v appcode="$appcode" -F"$config_del" '{ if ($1 == appcode ) print $0 }' | awk -v unique_host="$unique_host" -F"$config_del" '{ if ( $2 == unique_host ) print $0 }'" in multiple places, in case of updates to the command then I have to make the same changes in multiple places, i want to get rid of that, i can not use functions for this kind of substitutions

Last edited by pludi; 11-19-2010 at 06:37 AM.. Reason: code tags, please...
# 4  
Old 11-19-2010
Quote:
Originally Posted by gvinayagam
Thanks, So do you mean that pipline command should not be stored and reused ?

[...]
No, I'm just saying that you need to encapsulate the repeating code in another function Smilie
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