===== Unixscripts:argp.sh =====

**argp.sh**(1) is a **bash**(1) wrapper around **getopt**(1) ((
See the [[https://www.gnu.org/software/libc/manual/html_node/Argument-Syntax.html | rules ]] for processing options to see just how hard it is without **getopt**(1) !!!)) to make life much easier for script developers. It's used in most of my scripts - look at them for examples of use. There's just one essential file to install - the script itself. Put it somewhere on your path, typically in ''/usr/local/bin''.

To use **argp.sh**(1), a script pipes in a description of its options (in XML or plain text) and gets back the variables as processed by **getopt**(1) - as a plus it also provides automatic help and man page production. 

It buys you:
  * all the [[https://www.gnu.org/software/libc/manual/html_node/Argument-Syntax.html|goodness]] of **getopt**(1)
  * define options in one central place together with descriptions. 
  * fewer 'magic' and duplicated values in your code
  * better consistency between
    - the **getopt**(1) calling parameters, 
    - the case statement processing the user's options and 
    - the help/man pages
  * less spaghetti in your own code
  * much, much easier to maintain
  * automatic help-page and man-page printing using the same data sources
  * checking of option consistency at runtime
  * range checking of option values at runtime
  * pretty easy to use (just copy and paste from one of my example scripts)
  * portable to OS's without long option support - the help page adapts too

Note that **argp.sh(1)** deprecates an older script that I wrote called **process-getopt**(1).

There is also a 'c' version of **argp.sh**(1) in case you need speed.

=== Download & repo ===

  * Homepage, Releases and Repository: [[https://sourceforge.net/p/argpsh/wiki/Home/ | Sourceforge]]

To get the latest version of the full source code:
  svn checkout svn://svn.code.sf.net/p/argpsh/code/trunk argpsh-code

=== Sample usage ===

This is a simple wrapper around **find**(1) but it has enough options to make an interesting sample:

  #!/usr/bin/env bash
  initialise() {
      local TEMP
  
      PROG=$(basename $0)
      VERSION="1.2"
      TYPE="f"
      ARGUMENTS="[pattern]"
      SHORT_DESC="Search for filenames in sub-directories."
      USAGE="Presently this is just a shorthand for:
  
  find . -follow -type $TYPE -name '*pattern*' -print 2>/dev/null |sort"
  
      NEW_ARGS=( )
  
      ARGS="
  ARGP_DELETE=quiet
  ARGP_VERSION=$VERSION
  ARGP_PROG=$PROG
  ARGP_PREFIX=FOO_
  ##############################################################   
  #OPTIONS:
  #name=default sname arg       type range   description
  ##############################################################   
  EXCLUDE=''    x     directory s    ''      exclude directory.
  DIR='f'       d     ''        b    'd'     search for a directory rather than a file.
  CD=''         C     directory s    ''      search from this directory rather than cwd.
  ##############################################################   
  ARGP_ARGS=[--] $ARGUMENTS
  ARGP_SHORT=$SHORT_DESC
  ARGP_USAGE=$USAGE"
  
      TYPE='f'
  
      exec 4>&1
      eval "$(echo "$ARGS" | argp.sh "$@" 3>&1 1>&4 || echo exit $? )"
      exec 4>&-
  
      TYPE="$FOO_DIR"
      [[ "$FOO_CD" ]] && {
          cd "$FOO_CD" || exit 1
      }
  
      NEW_ARGS=( "$@" )
      return 0
  }
  
  main() {
      set -o noglob
      SEP=''
      for EXCLDIR in .svn .git nbproject .libs .deps CVS* $FOO_EXCLUDE; do
          EXCLDIRS+="$SEP -path */$EXCLDIR "
          SEP=" -o"
      done
  
      [[ "$FOO_VERBOSE" ]] && set -x
      find . -follow \( $EXCLDIRS \) -prune -o -type $TYPE -name "*$1*" -print 2>/dev/null |sort
  }
  
  initialise "$@" && set -- "${NEW_ARGS[@]:-}"
  
  main "$@"

Here is the output from the --help option auto-generated by **argps.sh**(1):

  Usage: ff [OPTION...] [--] [pattern]
  Presently this is just a shorthand for:
  
  find . -follow -type f -name '*pattern*' -print 2>/dev/null |sort
  Options:
  
    -C, --cd=directory         search from this directory rather than cwd.
    -d, --dir                  search for a directory rather than a file. Default
                               is 'f'.
    -v, --verbose              be verbose
    -x, --exclude=directory    exclude directory.
    -h, --help                 print this help message
    -V, --version              print version and exit