better Bash trace

_.sh

#!/bin/bash

# Define variables for adjustable verbosity
verbosity=2 #Start counting at 2 so that any increase to this will result in a minimum of file descriptor 3.  You should leave this alone.
maxverbosity=5 #The highest verbosity we use / allow to be displayed.  Feel free to adjust.

# Parse requested verbosity level and whether we're logging or not
while getopts ":vl" opt; do
  case $opt in
    v) (( verbosity=verbosity+1 ));;
    l) log="true" ;; 
  esac
done

# Opt-out logging: Use `script` utility to log output in case you want to review it later.  We call this script again but inside of `script` and add '-l' to prevent recursion.  If you don't want logs, add '-l' when you invoke the script.
[[ "$log" ==  "true" ]] || exec script --return --quiet --command "$0 -l $*" --append ${0}.log

printf "%s %d. %s\n" "Verbosity level set to:" "$verbosity" "Increase with '-v[v]'."

for v in $(seq 3 $verbosity) #Start counting from 3 since 1 and 2 are standards (stdout/stderr).
do
  (( "$v" <= "$maxverbosity" )) && eval exec "$v>&2"  #Don't change anything higher than the maximum verbosity allowed.
done

for v in $(seq $(( verbosity+1 )) $maxverbosity ) #From the verbosity level one higher than requested, through the maximum;
do
  (( "$v" > "2" )) && eval exec "$v>/dev/null" #Redirect these to bitbucket, provided that they don't match stdout and stderr.
done

function debug(){
	printf '\tdebug: %s%s%s\n' "$(tput setab 0)" "$BASH_COMMAND" "$(tput sgr0)" >&3
}

trap 'debug' DEBUG

printf '%s running at %s\n' "$(basename $0)" "$(date)"