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Why not take awk variable for?

Why not take awk variable for?

Why not take awk variable for?

for I in MAY JUN JUL AUG; do echo $I; cat final_subscriber_mOP.txt | grep -v -e rows -e --- -e s|awk '$1 ~ /$I/ {print $1, $2}' | sort -n | uniq -c; done

Thank you for support.

RE: Why not take awk variable for?


This is not really an Awk question as Awk can do nothing to access shell variables.

The usual solution is to have the shell expand that variable before the code is passed to Awk. But parameter expansion is not performed on single quoted ( ' ) strings :

CODE --> line

master # I='Something'

master # echo '$1 ~ /$I/ {print $1, $2}'
$1 ~ /$I/ {print $1, $2} 

The solution may be to enclose the string in double quotes ( " ), but then the shell will attempt to expand everything looking meaningful for it :

CODE --> line

master # echo "$1 ~ /$I/ {print $1, $2}"
 ~ /Something/ {print , } 

So to make quoting work as you wish, you have to either :


# interrupt the single quotes around the shell variable and quote it with double quotes
awk '$1 ~ /'"$I"'/ {print $1, $2}'

# escape everything you not want the shell to expand
awk "\$1 ~ /$I/ {print \$1, \$2}" 

Beside those the are 2 more ways the shell can make a value accessible to Awk :


# define an Awk variable from outside, using the -v ( or --assign ) option
awk -vJ="$I" '$1 ~ J {print $1, $2}'

# export the variable ( using the export shell builtin ) so Awk can access it as environment variable
awk '$1 ~ ENVIRON["I"] {print $1, $2}' 


RE: Why not take awk variable for?

Hi Feherke

Thanks you so much. I think that was it. Let me check your solution and let you know.

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