docopt for shell - make beautiful CLI with ease.
Status: working.
docopts : the command line wrapper for bash.
Most concepts are documented in the docopt (without S) manual - see docopt.org.
Many examples use associative arrays in Bash 4+, but there is legacy support for Bash 3.2 on macOS (OS X) or legacy GNU/Linux OS.
This is a bug fix release: v0.6.4-with-no-mangle-double-dash
This release will be maintained for compatibility, only fixes will be provided. The 0.6.4 version is fully compatible with
the previous version of docopts. Except for - handling in global mode, which produces an error.
docopts [options] -h <msg> : [<argv>...]
docopts [options] [--no-declare] -A <name> -h <msg> : [<argv>...]
docopts [options] -G <prefix> -h <msg> : [<argv>...]
docopts [options] --no-mangle -h <msg> : [<argv>...]
docopts parses the command line argument vector <argv> according to the
docopt string <msg> and echoes the results to standard
output as a snippet of Bash source code. Passing this snippet as an argument to
eval(1) is sufficient for handling the CLI needs of
most scripts.
Global mode, is the default historical output of docopts. It will output
globals variable for storing parsed result.
If <argv> matches one of the usage patterns defined in <msg>, docopts
generates code for storing the parsed arguments as Bash variables. As most
command line argument names are not valid Bash identifiers, some name mangling
will take place:
<Angle_Brackets>==>Angle_BracketsUPPER-CASE==>UPPER_CASE--Long-Option==>Long_Option-S==>S-4==> INVALID (without-G)
If one of the argument names cannot be mangled into a valid Bash identifier,
or two argument names map to the same variable name, docopts will exit with
an error, and you should really rethink your CLI, or use -A or -G.
If the double-dash is part of the <msg> the matched item -- will be skiped.
Note: You can use --no-mangle if you still want full input, this wont
produce output suitable for bash eval(1) but can be parsed by your own
code. Double-dash -- will be kept.
-G is a variant of Global mode, which prefixes the globals mangled named with
<prefix> + _ + Mangled_name. In this mode double-dash -- and single-dash
- will be kept and will be mangled.
--Long-Option==>prefix_Long_Option--==>prefix___-==>prefix__
Note that prefixed invalid mangled names still raise an error, if they resolve to invalid bash identifier.
Prefix gobals variable makes it easy to filter variable with grep or such, or to
avoid globals name collision.
Handling [-] in global mode is not supported and raises an error when trying to mangle -.
But works for any other modes including -G. This behavior differs from python's version of
docopts which would have skiped the positional - without error.
./docopts -h 'Usage: dump [-]' : -
docopts:error: Print_bash_global:Mangling not supported for: '-'
Single-dash can be catch easily by reading it into a FILENAME parameter:
./docopts -h 'Usage: prog parse FILENAME' : parse -
parse=true
FILENAME='-'then in your code:
f="$FILENAME"
if [[ $f == '-' ]] ; then
f=/dev/stdin
fiA working example is provided in examples/legacy_bash/cat-n_wrapper_example.sh
Alternatively, docopts can be invoked with the -A <name> option, which
stores the parsed arguments as fields of a Bash 4+ associative array called
<name> instead. However, as Bash does not natively support nested arrays,
they are faked for repeatable arguments with the following access syntax:
${args[ARG,#]} # the number of arguments to ARG
${args[ARG,0]} # the first argument to ARG
${args[ARG,1]} # the second argument to ARG, etc.
Associative mode don't skip double-dash -- it will be part of the keys
as boolean value present or not.
What ever output mode has been selected.
The arguments are stored as follows:
- Non-repeatable, valueless arguments:
trueif found,falseif not. This include double-dash--which must be specified as docopt syntax. - Repeatable valueless arguments: the count of their instances in
<argv> - Non-repeatable arguments with values: the value as a string if found, the empty string if not
- Repeatable arguments with values: a Bash array of the parsed values
Unless the --no-help option is given, docopts handles the --help
and --version options and their possible aliases specially,
generating code for printing the relevant message to standard output and
terminating successfully if either option is encountered when parsing <argv>.
Note however that this also requires listing the relevant option in
<msg> and, in --version's case, invoking docopts with the --version
option.
If <argv> does not match any usage pattern in <msg>, docopts will generate
code for exiting the program with status 64 EX_USAGE in sysexits(3)
and printing a diagnostic error message.
Note that due to the above, docopts can't be used to parse shell function
arguments: exit(1) quits the entire interpreter,
not just the current function.
This is the verbatim output of the --help:
Options:
-h <msg>, --help=<msg> The help message in docopt format.
Without argument outputs this help.
If - is given, read the help message from
standard input.
If no argument is given, print docopts's own
help message and quit.
-V <msg>, --version=<msg> A version message.
If - is given, read the version message from
standard input. If the help message is also
read from standard input, it is read first.
If no argument is given, print docopts's own
version message and quit.
-s <str>, --separator=<str> The string to use to separate the help message
from the version message when both are given
via standard input. [default: ----]
-O, --options-first Disallow interspersing options and positional
arguments: all arguments starting from the
first one that does not begin with a dash will
be treated as positional arguments.
-H, --no-help Don't handle --help and --version specially.
-A <name> Export the arguments as a Bash 4+ associative
array called <name>.
-G <prefix> Don't use associative array but output
Bash 3.2 compatible GLOBAL variables assignment:
<prefix>_{mangled_args}={parsed_value}
Can be used with numeric incompatible options
as well. See also: --no-mangle
--no-mangle Output parsed option not suitable for bash eval.
Full option names are kept. Rvalue is still
shellquoted. Extra parsing is required.
--no-declare Don't output 'declare -A <name>', used only
with -A argument.
--debug Output extra parsing information for debugging.
Output cannot be used in bash eval.
Bash 4+ and higher is the main target.
In order to use docopts with Bash 3.2 (for macOS and old GNU/Linux versions) by avoiding bash >4.x associative arrays,
you can:
- don't use the
-Aoption - use GLOBAL generated mangled variables
- use
-G<prefix>option to generate GLOBAL withprefix_ - use
-Gswitch withsource docopts.sh --auto -G(see example)
The docopts.sh helper allows the use of set -u, which
gives an error
on undefined variables in your scripts.
Unofficial strict mode for bash
should also work with docopts.sh, please report any issue with examples.
The helper has its own documentation here docs/README.md.
Find more examples in examples/ folder. Please report any non working example by creating an issue with examples.
The following example reads the help and version messages from standard input (docopts found in $PATH):
source examples/legacy_bash/rock_hello_world.sh
#!/usr/bin/env bash
# Example from README.md
PATH=$PATH:../..
eval "$(docopts -V - -h - : "$@" <<EOF
Usage: rock [options] <argv>...
Options:
--verbose Generate verbose messages.
--help Show help options.
--version Print program version.
----
rock 0.1.0
Copyright (C) 200X Thomas Light
License RIT (Robot Institute of Technology)
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
EOF
)"
if $verbose ; then
echo "Hello, world!"
fiThe following example, parses the help and version messages from script comments and pass them as command line arguments:
source examples/legacy_bash/rock_hello_world_with_grep.sh
#!/usr/bin/env bash
# Example from README.md
PATH=$PATH:../..
#? rock 0.1.0
#? Copyright (C) 200X Thomas Light
#? License RIT (Robot Institute of Technology)
#? This is free software: you are free to change and redistribute it.
#? There is NO WARRANTY, to the extent permitted by law.
##? Usage: rock [options] <argv>...
##?
##? Options:
##? --help Show help options.
##? --version Print program version.
help=$(grep "^##?" "$0" | cut -c 5-)
version=$(grep "^#?" "$0" | cut -c 4-)
eval "$(docopts -h "$help" -V "$version" : "$@")"
for arg in "${argv[@]}"; do
echo "$arg"
doneThe next example shows how using the Bash 4+ associative array with -A:
help="
Usage: example [--long-option-with-argument=value] <argument-with-multiple-values>...
"
eval "$(docopts -A args -h "$help" : "$@")"
if ${args[subcommand]} ; then
echo "subcommand was given"
fi
if [ -n "${args[--long-option-with-argument]}" ] ; then
echo "${args[--long-option-with-argument]}"
else
echo "--long-option-with-argument was not given"
fi
i=0
while [[ $i -lt ${args[<argument-with-multiple-values>,#]} ]] ; do
echo "$i: ${args[<argument-with-multiple-values>,$i]}"
i=$[$i+1]
donedocopts was first developed by Lari Rasku [email protected] and was written in Python based on the
docopt Python parser.
The current version is written in go and is almost 100% compatible with previous Python-based docopts.
See section Global mode for incompatibly details and provided work around.
Please report any non working code with issue and examples.
Starting at release: 0.7.0 a new lib API based on JSON will be introduced:
See and contribute on the docopts Wiki.
You only have to drop the binary, and optionally also the docopts.sh lib helper, in a directory on your PATH.
The binary is standalone and statically linked, so it runs everywhere.
See build section.
With root privileges you could do:
cp docopts docopts.sh /usr/local/bin
Pre-built Go binaries for some OS (32 and 64 bits) are attached to releases.
We provide a download helper:
git clone https://github.com/docopt/docopts.git
cd docopts
./get_docopts.shYou should get a renamed docopts in the current folder.
Put it in your PATH:
sudo cp docopts docopts.sh /usr/local/binThe cloned repository is no more used at this stage, but still contains a lot of bash examples.
Learn more about pre-built binaries.
We encourage you to build your own binary, which is easy once you have Go installed. Or find a local golang developer that you trust and ask her, in exchange for a beer or two, if she could build it for you. ;)
Requires a Go workspace.
local build:
(also done with our Makefile default target: make)
go get github.com/docopt/docopt-go
go get github.com/docopt/docopts
cd src/github.com/docopt/docopts
go build docopts.go
cross compile for 32 bit:
env GOOS=linux GOARCH=386 go build docopts.go
or via Makefile:
cd src/github.com/docopt/docopts
make all
make test
Tested builds are built on:
go version go1.17.1 linux/amd64
Warning: may be not up-to-date feature list.
The docopts.sh helper is an extra bash library that you can source in your shell script.
This library provides some bash helpers and is not required in order to use docopts. See docopts.sh
documentation.
docopts doesn't need a python interpreter anymore, so it works on any legacy system too.
As of 2021-09-15
docoptsis able to reproduce almost 100% of the python version.- unit tests for Go are provided, so hack as you wish.
- 100% of
language_agnostic_tester.pytests pass (GNU/Linux 64bits). bats-coreunittests and functional testing are provided too.
Read the doc for developer.
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