Complex find and replace only 1st instance string with dynamic combination

test.txt is the dynamic file but some of combination are fix

like below are the lines

;wonder_off =
;wonder_off = disabled
wonder_off =
wonder_off = disabled

the test.txt can content them in any order

#cat test.xt 
;wonder_off =
;wonder_off = disabled
wonder_off =
wonder_off = disabled

OR

#cat test.xt 
wonder_off =
wonder_off = disabled
;wonder_off =
;wonder_off = disabled

I need to find and replace only 1st instatnce of the test.xt

example if:

#cat test.xt 
;wonder_off =
;wonder_off = disabled
wonder_off =
wonder_off = disabled

find ";wonder_off =" and replace it with "wonder_off = "Enabled,working_bar,extra_deft""

Result should be :

cat test.xt 
wonder_off = "Enabled,working_bar,extra_deft"
;wonder_off = disabled
wonder_off =
wonder_off = disabled

I can managed to get only 1st line which can be any combination i mention above

#VAR=`cat test.xt | head -1`


#echo $VAR
;wonder_off =

How can I Find only 1st instance with matching string and replace it with "wonder_off = "Enabled,working_bar,extra_deft""

Hi,
Try this untested code

awk 'BEGIN{done=0;}$0 ~ /;wonder_off=/{if(done ==0){gsub(/;wonder_off/,";wonder_off=\"Enabled,working_bar\"",$0);done=1;}print;}' file

pls configure substitute string based on your req.
Cheers,
Ranga:-)

replace FILE with your file name :

sed -i "`grep -n ^\;wonder_off FILE|cut -d':' -f1 |head -1`s/\;wonder_off =/wonder_off = \"Enabled,working_bar,extra_deft\"/" FILE

for reminder, there are two FILE to replace in the code

Thanks you both

but you missed one VERY IMP thing

the first line can be anything from the combination as i mention
can be
;wonder_off =
can be
;wonder_off = disabled
can be
wonder_off =
can be
wonder_off = disabled

oh, not a problem , just add a $ at the end of grep regex :

sed -i "`grep -n "^\;wonder_off$" FILE|cut -d':' -f1 |head -1`s/\;wonder_off =/wonder_off = \"Enabled,working_bar,extra_deft\"/" FILE

and its done
now replace

;wonder_off

to anything you want to find , and replace

;wonder_off =

to anything you want to replace.

$ sed 's,;wonder_off =$,wonder_off = "Enabled\,working_bar\,extra_deft",1' infile