Regex pattern tester. Related to https://twitter.com/freebsdfrau/status/1245253969447809024?s=20

re-test.sh

#!/bin/sh

#
# Test several regex patterns against the characters in the ASCII printable range
# Related to https://twitter.com/freebsdfrau/status/1245253969447809024?s=20
#

seq 33 126 | awk '
BEGIN {
  split("[-_[:alpha:]] [-[:alpha:]_] [_[:alpha:]-] [[:alpha:]_-]", tests, "[[:blank:]]+")
}

{ 
  char = sprintf("%c", $1);
  input = input char;
  for (key in tests) {
    results[tests[key]] = results[tests[key]] (match(char, tests[key]) ? "x" : ".");
  }
}



END {
  print "input        ", input
  for (key in results)
    print key, results[key]
}
' | column -s: