two files join_tool.sh "$jointype" "$output_format" "$empty_string_filler" "$delimiter" "$ignore_case" "$input1" "$column1" "$input2" "$column2" "$output" BOTH 1st & 2nd file. 1st but not in 2nd file. [-v 1] 2nd but not in 1st file. [-v 2] both 1st & 2nd file, plus unpairable lines from 1st file. [-a 1] both 1st & 2nd file, plus unpairable lines from 2st file. [-a 2] All Lines [-a 1 -a 2] comma (,) colons (:) single space dot (.) dash (-) pipe (|) underscore (_) tab Case sensitive Case INsensitive [-i]