Hello Ken6503,

For 1st query:
gsub(/s\(/,X,$NF) means it will substitute strings (/ and \)with NULL value. (I have used \(/ because (,) are meta characters and to
tell awk not to take their special meaning and take characters as it is we use escape character \)

For 2nd query:
Thank you for pointing out same, Yes you are right we can we can read the file once also, so no need to put FNR==NR condition in it,
so code can be reduce to as follows.(Not tested in different scenarios)

Code:

awk '{if(NF>1){A[$1]=$1;gsub(/s\(/,X,$NF);gsub(/\)$/,X,$NF);B[$NF]=$NF} else {gsub(/s\(/,X,$NF);gsub(/\)$/,X,$NF);B[$NF]=$NF}} END{for(j in A){delete B[j]}for(u in B){print B[u]}}' Input_file

Output will be as follows.

Code:

deptnm-ocode-00-dum
deptnm-appnm-ecode
deptnm-on-rundt-bp
deptnm-on-rundt-run
deptnm-appnm-ecode-dld
deptnm-ocode-30-ddd
deptnm-ocode-50-curcnt

Thanks,
R. Singh