So here it is my solution. I wanted to be able to handle boolean flags without hyphen, with one hyphen, and with two hyphen as well as parameter/value assignment with one and two hyphens.
# Handle multiple types of arguments and prints some variables
#
# Boolean flags
# 1) No hyphen
# create Assigns `true` to the variable `CREATE`.
# Default is `CREATE_DEFAULT`.
# delete Assigns true to the variable `DELETE`.
# Default is `DELETE_DEFAULT`.
# 2) One hyphen
# a Assigns `true` to a. Default is `false`.
# b Assigns `true` to b. Default is `false`.
# 3) Two hyphens
# cats Assigns `true` to `cats`. By default is not set.
# dogs Assigns `true` to `cats`. By default is not set.
#
# Parameter - Value
# 1) One hyphen
# c Assign any value you want
# d Assign any value you want
#
# 2) Two hyphens
# ... Anything really, whatever two-hyphen argument is given that is not
# defined as flag, will be defined with the next argument after it.
#
# Example:
# ./parser_example.sh delete -a -c VA_1 --cats --dir /path/to/dir
parser() {
# Define arguments with one hyphen that are boolean flags
HYPHEN_FLAGS="a b"
# Define arguments with two hyphens that are boolean flags
DHYPHEN_FLAGS="cats dogs"
# Iterate over all the arguments
while [ $# -gt 0 ]; do
# Handle the arguments with no hyphen
if [[ $1 != "-"* ]]; then
echo "Argument with no hyphen!"
echo $1
# Assign true to argument $1
declare $1=true
# Shift arguments by one to the left
shift
# Handle the arguments with one hyphen
elif [[ $1 == "-"[A-Za-z0-9]* ]]; then
# Handle the flags
if [[ $HYPHEN_FLAGS == *"${1/-/}"* ]]; then
echo "Argument with one hyphen flag!"
echo $1
# Remove the hyphen from $1
local param="${1/-/}"
# Assign true to $param
declare $param=true
# Shift by one
shift
# Handle the parameter-value cases
else
echo "Argument with one hyphen value!"
echo $1 $2
# Remove the hyphen from $1
local param="${1/-/}"
# Assign argument $2 to $param
declare $param="$2"
# Shift by two
shift 2
fi
# Handle the arguments with two hyphens
elif [[ $1 == "--"[A-Za-z0-9]* ]]; then
# NOTE: For double hyphen I am using `declare -g $param`.
# This is the case because I am assuming that's going to be
# the final name of the variable
echo "Argument with two hypens!"
# Handle the flags
if [[ $DHYPHEN_FLAGS == *"${1/--/}"* ]]; then
echo $1 true
# Remove the hyphens from $1
local param="${1/--/}"
# Assign argument $2 to $param
declare -g $param=true
# Shift by two
shift
# Handle the parameter-value cases
else
echo $1 $2
# Remove the hyphens from $1
local param="${1/--/}"
# Assign argument $2 to $param
declare -g $param="$2"
# Shift by two
shift 2
fi
fi
done
# Default value for arguments with no hypheb
CREATE=${create:-'CREATE_DEFAULT'}
DELETE=${delete:-'DELETE_DEFAULT'}
# Default value for arguments with one hypen flag
VAR1=${a:-false}
VAR2=${b:-false}
# Default value for arguments with value
# NOTE1: This is just for illustration in one line. We can well create
# another function to handle this. Here I am handling the cases where
# we have a full named argument and a contraction of it.
# For example `--arg1` can be also set with `-c`.
# NOTE2: What we are doing here is to check if $arg is defined. If not,
# check if $c was defined. If not, assign the default value "VD_"
VAR3=$(if [[ $arg1 ]]; then echo $arg1; else echo ${c:-"VD_1"}; fi)
VAR4=$(if [[ $arg2 ]]; then echo $arg2; else echo ${d:-"VD_2"}; fi)
}
# Pass all the arguments given to the script to the parser function
parser "$@"
echo $CREATE $DELETE $VAR1 $VAR2 $VAR3 $VAR4 $cats $dir