bash-params

Simple parameter parsing and help message generation for bash scripts.

Note: a --help parameter is created by the script.

Usage

The most basic use case is to create a parameter to parse. A variable with the parameter name is created. Kepping only the uppercased latin letters.

source bash-params.sh

param-def param-name

param-parse "$@"

echo ${PARAMNAME}

Call the script:

$ bash script.sh --param-name value
value

You can also specify short one-dash options. If you specify several names, the corresponding variable is generated from the first one (it is therefore not recommended to place the one-letter flags first).

param-def param-name p # the variable will be *PARAMNAME*
param-def b baram-name # the variable will be *B*

Finally you can add a default value and an argument description after the flags.

param-def param-name :! "Parameter description" :- "default value"

Customizing the parse

You can customize how a parameter is treated during the parse. In order to do so, before calling param-parse "$@" you must redefine the corresponding parse function parameters-param-name where param-name is the name of your parameter. This function is given all the arguments following its own one and must return the number of arguments that it consumes.

source bash-param.sh

param-def single-flag f :! "This parameter is a toggle flag, it does not consume arguments"
param-def eat-two :! "This parameter eats two arguments"

parameters-single-flag () {
  SINGLEFLAG=1;
  return 0;
}

parameters-eat-two () {
  ONE=$1;
  TWO=$2;
  return 2;
}

param-parse "$@"

echo ${SINGLEFLAG}
echo ${ONE}
echo ${TWO}

This will give :

$ bash script.sh -f --eat-two 42 56
1
42
56