Kindly modify my script, because I want to search the word "dBm" in Column 1,3, and 4 of File.csv and return all unmatched lines/records 'cause "dBm" need to be deleted on the file.
cat File.csv | grep -v dBm | sort -u -t '|' -k 1,1 -k 3,4 > Result.csv
Sample File.csv
RefNum|Date|Info|LTC|ICD|MLBB
ABC123|010119|19 dBm||Milk|MII9
DEF456|010119|21|-5 dBm|Choco|KK20
GHI789|010219|||C2|AA30
JKL111|010219|54|17||SK10
Sample Result.csv
RefNum|Date|Info|LTC|ICD|MLBB
GHI789|010219|||C2|AA30
JKL111|010219|54|17||SK10
Badly needed you're help! Cheers.

egrep -v dBm File.csv > Result.csv? do the other columns take dBm value as well and should not be removed?