Extract info using awk - awk

Question

My input is:
group;|line1_1|line2_2|line3_3
I want to extract the inforamtion line1,line2,line3 as below output:
line1,line2,line3
I have tried by using the following command but not executable:
LINE="group;|line1_1|line2_2|line3_3"; echo $LINE | awk -F ";" '{print $2}' | awk -F "|" '{for(i=1;i<=NF;++i){print $i | system("cut -d _ -f1")}}'

Answer 1

Considering that your actual Input_file is same as shown samples. Could you please try following.
awk -F'|' '{for(i=2;i<=NF;i++){sub(/_.*/,"",$i);val=val?val OFS $i:$i};print val;val=""}' OFS="," Input_file
2nd Solution: Only using sub and gsub of awk here.
awk '{sub(/^[^|]*\|/,"");gsub(/_[0-9]\|/,",");sub(/_[0-9]$/,"")} 1' Input_file
OR
awk '{gsub(/^[^|]*\||_[0-9]$/,"");gsub(/_[0-9]\|/,",")} 1' Input_file
Output will be as follows.
line1,line2,line3
Explanation: Adding explanation for above code now.
awk -F'|' ' ##Setting field separator as | here for all lines.
{ ##Starting block here.
for(i=2;i<=NF;i++){ ##Starting for loop starting form i=2 to till value of NF here.
sub(/_.*/,"",$i) ##Using sub for substitution from _ to till everything with NULL in value of $i.
val=val?val OFS $i:$i ##Creating variable val and concatenate its own value if it is having NON ZERO value else save in it for 1st time.
} ##Close for loop block here.
print val ##Printing value of val here.
val="" ##Nullifying value of variable val here.
}' OFS="," Input_file ##Setting value of OFS to comma here and mentioning Input_file name here.