shithub: trueawk

ref: 94e4c04561f7b9c2a3e7ef498fbfe7ce5b20ed40
dir: /testdir/t.gsub4/

length($1) == 0 { next }

{gsub("[" $1 "]","(&)"); print}
{gsub("[" $1 "]","(\\&)"); print}