How to parse command-line flags in Tcl

parse-flags.tcl

#!/usr/bin/env tclsh

# get flag parser from the standard library (tcllib)
package require cmdline

# set version of our command-line application (this file)
set version 0.0.1

# declare what flags to parse
# format: {flag  default description}
set options {
  {n.arg       "" "Name of the person to greet"}
  {name.arg    "" "Name of the person to greet"}
  {m.arg       "" "Message to greet with"}
  {message.arg "" "Message to greet with"}
}

# define help message
set usage "v$version\n\nUsage: worktree \[options] url ...\n\nOptions:"

# do the parsing 
try {
  array set params [::cmdline::getoptions argv $options $usage]
} trap {CMDLINE USAGE} {msg o} {
  puts $msg
  exit 1
}

puts "name:    $params(name)"
puts "message: $params(message)"