CODEWITHSUNDEEP
shellunixawk
user3478415
user3478415

Reputation: 45

escape characters within awk argument

in a unix shell script I have

filename=myfile
LOG=/dir/log*
j=`awk '/AAAA/ && /BBB/ && /${filename}/ && /CCC/' ${LOG}`

but when the script runs, with set -x I see:

awk /AAA/ && /BBB/ && /${filename}/ && /CCC/ /dir/log1 /dir/log2

How can I escape the ${filename} variable within the awk argument so that it resolves correctly ?

To illustrate what I am trying to do

I have a file called /tmp/S20150814.001 which contains

This line contains AAAA and BBB and CCC and bcd_input_13082015_0800.txt

In my script, if I use

MYLOG=/tmp/S20150814.001
j=`awk '/AAAA/ && /BBB/ && /bcd_input_13082015_0800.txt/ && /CCC/' ${MYLOG}`
if [[ ${#j} -gt 0 ]]
then

and run the script I see

+ + awk /AAAA/ && /BBB/ && /bcd_input_13082015_0800.txt/ && /CCC/      /tmp/S20150814.001
j=This line contains AAAA and BBB and CCC and bcd_input_13082015_0800.txt
+ [[ 71 -gt 0 ]]

but if I change the script to

MYLOG=/tmp/S20150814.001
filename=bcd_input_13082015_0800.txt
j=$(awk -v filename="$filename" '/AAAA/ && /BBB/ && $0==filename && /CCC/' ${MYLOG})
if [[ ${#j} -gt 0 ]]
then

and run it, I get

+ + awk -v filename=bcd_input_13082015_0800.txt /AAAA/ && /BBB/  &&  $0==filename && /CCC/ /tmp/S20150814.001
j=
+ [[ 0 -gt 0 ]]

Upvotes: 0

Views: 448

Answers (2)

user3478415
user3478415

Reputation: 45

I got this to work by

j=$(awk -v filename="$filename" '/AAAA/ && /BBB/ && $0 ~ filename && /CCC/' ${MYLOG})

ie a space was needed before and after the "~"

Upvotes: 0

ghoti
ghoti

Reputation: 46856

You shouldn't put filenames inside the code of your awk script like that. If you need to pass in a variable, awk has an option for that.

j=$(awk -v filename="$filename" '/AAAA/ && /BBB/ && $0~filename && /CCC/' ${LOG})

Or, since your filename might contain characters interpreted as part of a regular expression, perhaps you really want:

j=$(awk -v filename="$filename" '/AAAA/ && /BBB/ && $0==filename && /CCC/' ${LOG})

See also: https://stackoverflow.com/a/9712555/1072112 for some help on how various types of quotes work.

Upvotes: 5

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