Is it possible to pass variable from awk to shell back

Shell Programming and Scripting
1

I am passing a varaible to from Shell to awk then I am doing some maniplation for that variable inside awk. I want that maniplated variable value back to shell , Is this possible .Please let me know.

2

Yep. it is always possible.
for eg:

a =`ls -l | awk '{print $8}'

should work.
if the output is more than 1 line. you can redirect the output to a intermediate file and use it later.

thx,
Siva

3

Hi,

I tried the following code:

]

This runs well, and provide me with the correct answer.

But when I redirect this command output to a variable, the value of the variable is not set.

Please advice what am I doing incorrectly in this case.

Thanks and Best Regards
Aditya

4

The reason is you have to tell the shell to feed the result - the stdout of the command - back to the variable:

variable="$( command1 | command2 | command3 )"

This will open a subshell, execute the pipeline and put the final output of command3 into the variable.

Btw. you will often see backticks recommended:

var=`command1 | command2 | command3`

This does basically the same, but is only possible in modern shells because they try to be compatible. Do NOT use this but the above mentioned construction.

bakunin

5

Thanks for the quick reply.
I tried out what you suggested:

set DataLine = "$( echo $CurrentLine | awk -F'[ :]' '{ print $1 }' )"
echo $DataLine

set DataLine = "$( echo $CurrentLine | awk -F'[ :]' '{ print $1 }' )"
echo $DataLine

But still the output for the DataLine variable is empty.
I hope I understood it correctly.

Thanks and Best Regards
Aditya

6

What is the value of CurrentLine?

7

CurrentLine is a some data that has : as seperator.

8

There are no special charaters in the line data.
I gues some of the combination of data charaters are converted to different smileys out here.

9

Try:

DataLine=$(echo $CurrentLine | awk -F'[ :]' '{ print $1 }')

without spaces around the "=" sign!

Regards

10

Thanks a ton Franklin52. It worked real well.

Thanks and Best Regards
Aditya

11

Another way than may be useful for setting multiple variables:

$ CurrentLine="The_Datas:Rest_of_line"
$ eval $(echo $CurrentLine | awk -F'[ :]' '{ print "DataLine=\"" $1 "\"\nRestLine=\"" $2 "\""}')
$ echo "<$DataLine> <$RestLine>"
<The_Datas> <Rest_of_line>
$

The eval command with debug trace :

$ set -x
$ eval $(echo $CurrentLine | awk -F'[ :]' '{ print "DataLine=\"" $1 "\"\nRestLine=\"" $2 "\""}')
++ echo The_Datas:Rest_of_line
++ awk '-F[ :]' '{ print "DataLine=\"" $1 "\"\nRestLine=\"" $2 "\""}'
+ eval 'DataLine="The_Datas"' 'RestLine="Rest_of_line"'
++ DataLine=The_Datas
++ RestLine=Rest_of_line
$

Jean-Pierre.

12

eval $(echo $CurrentLine | awk -F'[ :]' '{ print "DataLine=\"" $1 "\"\nRestLine=\"" $2 "\""}')

When I execute the script as you mentioned , I get blank spaces. I am using Korn Shell. Please let me know if any other way doing this.

Thanks
SHivannad

13

Execute the command with the -x option of the KSH like in my previous post and show us the output.

Jean-Pierre.