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Help Message for Shell Scripts

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Re: Help Message for Shell Scripts

#11

Post by dragonwriter »

mey wrote: post #7

Handling of arguments is one of the reasons I reach for Python or Powershell instead of a bash script when writing my own stuff. https://docs.python.org/3/library/argparse.html is great. Powershell has the Param keyword that functions like argparse in Python https://docs.microsoft.com/en-us/powershell/module/microsoft...

> https://docs.python.org/3/library/argparse.html is great

Argparse is okay (and being in stdlib makes it always-available), but it's no click. https://click.palletsprojects.com/en/7.x/

Re: Help Message for Shell Scripts

#12

Post by jandrese »

adrianmonk wrote: post #6
jandrese wrote: post #4

Hmm: % sed -rn 's/^### ?//;T;p' testfile sed: 1: "s/^### ?//;T;p": invalid command code T Looks like it might need GNU Sed or something. But honestly if I want to read the top of the file less works just as well.

Yeah, "man sed" on my machine says, "This is a GNU extension." You could do the same thing with awk instead: awk '{ if (sub("^### ?", "")) { print; } else { exit; } }'

Well sure, there are tons of ways to do this in other languages. :)

Perl for example was made for problems like this.

   perl -ne 'print if ( s/^### ?// )'

Re: Help Message for Shell Scripts

#13

Post by yjftsjthsd-h »

psophis wrote: post #8
adrianmonk wrote: post #5

You can also use a "here document" help() { cat Options: Input file to read. Output file to write. Use '-' for stdout. -h Show this message. EOH } If the indentation bugs you, you can use a simpler sed trick to remove leading space so that you can indent it as desired: help() { sed -e 's/ //' Options: Input file to read. Output file to write. Use '-' for stdout. -h Show this message. EOH }

You can also use add a hyphen ( https://linuxhint.com/bash-heredoc-tutorial/

Oh, that's nice! And in spite of the labeling on that page, it doesn't seem to be a BASHism; it at least works in dash, too.

Re: Help Message for Shell Scripts

#14

Post by 40four »

dragonwriter wrote: post #11
mey wrote: post #7

Handling of arguments is one of the reasons I reach for Python or Powershell instead of a bash script when writing my own stuff. https://docs.python.org/3/library/argparse.html is great. Powershell has the Param keyword that functions like argparse in Python https://docs.microsoft.com/en-us/powershell/module/microsoft...

> https://docs.python.org/3/library/argparse.html is great Argparse is okay (and being in stdlib makes it always-available), but it's no click. https://click.palletsprojects.com/en/7.x/

Thumbs up for 'Click'. I used it for a project once, and I was really happy with it. Easy to use, good docs. Would use it again.

Re: Help Message for Shell Scripts

#17

Post by ahnick »

I like the idea of combining the header with the help documentation to reduce the number of areas to maintain in smaller scripts. For larger scripts though, I think I'd still prefer to have a separate function, so that the help documentation doesn't overwhelm the initial viewing of the actual code.

I also like to feed a heredoc directly into man, which allows you to achieve nicer formatting for the help documentation. Something like this...

  man -l -
See encpass.sh for a working example of this -> https://github.com/plyint/encpass.sh/blob/master/encpass.sh

Re: Help Message for Shell Scripts

#18

Post by koala_man »

adrianmonk wrote: post #5

You can also use a "here document" help() { cat Options: Input file to read. Output file to write. Use '-' for stdout. -h Show this message. EOH } If the indentation bugs you, you can use a simpler sed trick to remove leading space so that you can indent it as desired: help() { sed -e 's/ //' Options: Input file to read. Output file to write. Use '-' for stdout. -h Show this message. EOH }

I believe the point of the article's method is that it allows you to document your script with code comments, and then reuse the same text for help output

Re: Help Message for Shell Scripts

#19

Post by lolsal »

ahnick wrote: post #17

I like the idea of combining the header with the help documentation to reduce the number of areas to maintain in smaller scripts. For larger scripts though, I think I'd still prefer to have a separate function, so that the help documentation doesn't overwhelm the initial viewing of the actual code. I also like to feed a heredoc directly into man, which allows you to achieve nicer formatting for the help documentation…

> so that the help documentation doesn't overwhelm the initial viewing of the actual code.

That is a very strange argument to me. You find that more cumbersome than jumping around to random functions?

Re: Help Message for Shell Scripts

#20

Post by Spivak »

mey wrote: post #7

Handling of arguments is one of the reasons I reach for Python or Powershell instead of a bash script when writing my own stuff. https://docs.python.org/3/library/argparse.html is great. Powershell has the Param keyword that functions like argparse in Python https://docs.microsoft.com/en-us/powershell/module/microsoft...

But handling args isn't that bad in bash.

    while [[ $# -gt 0 ]]; do
      case "$1" in
         -h|--help)
           do_help
           exit
           ;;
         -v|--version)
           do_version
           exit
           ;;
         -d|--debug)
           debug=true
           shift
           ;;
         -a|--arg)
           arg_value=$2
           shift 2
           ;;
      esac
    done
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