Awk: splitting a field

+1. The 3rd arg for split() is a field separator which is a regexp with additional properties, not a string. The regexp delimiter is /, not " which is the string delimiter. Awk can construct regexps from strings by analyzing the context in which a string is used to see if it is a regexp context but it's best to keep your code clear and simple and use regexp delimiters for regexps unless you have a specific reason not to: split($1,a,/%/).

@EdMorton I am aware the 3rd arg is regex but didn't know it doesn't have to be a string. Edited as you suggested. Thanks for the information!

Unce upon a time in old, broken awk it had to be a string but all modern awks support RE delimiters. The difference between using a string and an RE is that with a string you have to double-escape any RE metachars that you want taken literally since awk uses up one of the escapes when it converts the string to an RE. The time to use string delimiters is when you want to construct an RE from a string plus a variable (split($0,a,somevar"etc")) or I sometimes use them for slightly improved readability when the RE is a forward-slash (split($0,a,"/") vs split($0,a,/\//)).