287 lines
12 KiB
Bash
287 lines
12 KiB
Bash
#!/bin/bash
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# https://blog.anthonyaxenov.ru/bash-args/
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# https://gist.github.com/anthonyaxenov/d53c4385b7d1466e0affeb56388b1005
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#########################################################################
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# #
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# Argument parser for bash scripts #
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# #
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# Author: Anthony Axenov (Антон Аксенов) #
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# Version: 1.5 #
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# License: MIT #
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# #
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#########################################################################
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# #
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# With 'getopt' you cannot combine different #
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# arguments for different nested functions. #
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# #
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# 'getopts' does not support long arguments with #
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# values (like '--foo=bar'). #
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# #
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# These functions supports different arguments and #
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# their combinations: #
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# -a -b -c #
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# -a avalue -b bvalue -c cvalue #
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# -cab bvalue #
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# --arg #
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# --arg=value -ab -c cvalue --foo #
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# #
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# Tested in Ubuntu 20.04.2 LTS in: #
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# bash 5.0.17(1)-release (x86_64-pc-linux-gnu) #
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# zsh 5.8 (x86_64-ubuntu-linux-gnu) #
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# #
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#########################################################################
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# #
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# Version history: #
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# v1.0 - initial #
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# v1.1 - arg(): improved skipping uninteresting args #
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# - arg(): check next arg to be valid value #
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# v1.2 - removed all 'return' statements #
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# - arg(): error message corrected #
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# - new examples #
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# v1.3 - argl(): improved flag check #
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# - some text corrections #
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# v1.4 - new function argn() #
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# - some text corrections #
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# v1.5 - arg(), grep_match(): fixed searching for -e argument #
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# - grep_match(): redirect output into /dev/null #
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# #
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#########################################################################
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#purpose Little helper to check if string matches PCRE
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#argument $1 - some string
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#argument $2 - regex
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#exitcode 0 - string valid
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#exitcode 1 - string is not valid
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grep_match() {
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printf "%s" "$1" | grep -qP "$2" >/dev/null
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}
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#purpose Find short argument or its value
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#argument $1 - (string) argument (without leading dashes; only first letter will be processed)
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#argument $2 - (number) is it flag? 1 if is, otherwise 0 or nothing
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#argument $3 - (string) variable to return value into
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# (if not specified then it will be echo'ed in stdout)
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#returns (string) 1 (if $2 == 1), value (if correct and if $2 != 1) or nothing
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#usage To get value into var: arg v 0 myvar or myvalue=$(arg 'v')
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#usage To find flag into var: arg f 1 myvar or flag=$(arg 'f')
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#usage To echo value: arg v
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#usage To echo 1 if flag exists: arg f
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arg() {
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local need=${1:0:1} # argument to find (only first letter)
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[ $need ] || {
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echo "Argument is not specified!" >&2
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exit 1
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}
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local isflag=$2 || 0 # should we find the value or just the presence of the $need?
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local retvar=$3 || 0 # var to return value into (if 0 then value will be echo'ed in stdout)
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local args=(${MAIN_ARGS[0]}) # args we need are stored in 1st element of MAIN_ARGS
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for ((idx=0; idx<${#args[@]}; ++idx)) do # going through args
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local arg=${args[$idx]} # current argument
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# skip $arg if it starts with '--', letter or digit
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grep_match "$arg" "^(\w{1}|-{2})" && continue
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# clear $arg from special and duplicate characters
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# e.g. 'fas-)dfs' will become 'fasd'
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local chars="$(printf "%s" "${arg}" | tr -s [${arg}] | tr -d "[:punct:][:blank:]")"
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# now we can check if $need is one of $chars
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if grep_match "-$need" "^-[$chars]$"; then # if it is
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if [[ $isflag = 1 ]]; then # and we expect it as a flag
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# then return '1' back into $3 (if exists) or echo in stdout
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[ $retvar ] && eval "$retvar='1'" || echo "1"
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else # but if $arg is not a flag
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# then get next argument as value of current one
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local value="${args[$idx+1]}"
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# check if it is valid value
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if grep_match "$value" "^\w+$"; then
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# and return it back back into $3 (if exists) or echo in stdout
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[ $retvar ] && eval "$retvar='$value'" || echo "$value"
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break
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else # otherwise throw error message into stderr (just in case)
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echo "Argument '$arg' must have a correct value!" >&2
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break
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fi
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fi
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fi
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done
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}
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#purpose Find long argument or its value
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#argument $1 - argument (without leading dashes)
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#argument $2 - is it flag? 1 if is, otherwise 0 or nothing
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#argument $3 - variable to return value into
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# (if not specified then it will be echo'ed in stdout)
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#returns (string) 1 (if $2 == 1), value (if correct and if $2 != 1) or nothing
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#usage To get value into var: arg v 0 myvar or myvalue=$(arg 'v')
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#usage To find flag into var: arg f 1 myvar or flag=$(arg 'f')
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#usage To echo value: arg v
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#usage To echo 1 if flag exists: arg f
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argl() {
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local need=$1 # argument to find
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[ $need ] || {
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echo "Argument is not specified!" >&2
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exit 1
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}
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local isflag=$2 || 0 # should we find the value or just the presence of the $need?
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local retvar=$3 || 0 # var to return value into (if 0 then value will be echo'ed in stdout)
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local args=(${MAIN_ARGS[0]}) # args we need are stored in 1st element of MAIN_ARGS
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for ((idx=0; idx<${#args[@]}; ++idx)) do
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local arg=${args[$idx]} # current argument
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# if we expect $arg as a flag
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if [[ $isflag = 1 ]]; then
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# and if $arg has correct format (like '--flag')
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if grep_match "$arg" "^--$need"; then
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# then return '1' back into $3 (if exists) or echo in stdout
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[ ! $retvar = 0 ] && eval "$retvar=1" || echo "1"
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break
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fi
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else # but if $arg is not a flag
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# check if $arg has correct format (like '--foo=bar')
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if grep_match "$arg" "^--$need=.+$"; then # if it is
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# then return part from '=' to arg's end as value back into $3 (if exists) or echo in stdout
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[ ! $retvar = 0 ] && eval "$retvar=${arg#*=}" || echo "${arg#*=}"
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break
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fi
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fi
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done
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}
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#purpose Get argument by its index
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#argument $1 - (number) arg index
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#argument $2 - (string) variable to return arg's name into
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# (if not specified then it will be echo'ed in stdout)
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#returns (string) arg name or nothing
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#usage To get arg into var: argn 1 myvar or arg=$(argn 1)
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#usage To echo in stdout: argn 1
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argn() {
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local idx=$1 # argument index
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[ $idx ] || {
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error "Argument index is not specified!"
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exit 1
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}
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local retvar=$2 || 0 # var to return value into (if 0 then value will be echo'ed in stdout)
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local args=(${MAIN_ARGS[0]}) # args we need are stored in 1st element of MAIN_ARGS
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local arg=${args[$idx]} # current argument
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if [ $arg ]; then
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[ ! $retvar = 0 ] && eval "$retvar=$arg" || echo "$arg"
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fi
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}
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# Keep in mind:
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# 1. Short arguments can be specified contiguously or separately
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# and their order does not matter, but before each of them
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# (or the first of them) one leading dash must be specified.
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# Valid combinations: '-a -b -c', '-cba', '-b -ac'
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# 2. Short arguments can have values and if are - value must go
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# next to argument itself.
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# Valid combinations: '-ab avalue', '-ba avalue', '-a avalue -b'
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# 3. Long arguments cannot be combined like short ones and each
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# of them must be specified separately with two leading dashes.
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# Valid combinations: '--foo --bar', '--bar --foo'
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# 4. Long arguments can have a value which must be specified after '='.
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# Valid combinations: '--foo=value --bar', '--bar --foo=value'
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# 5. Values cannot contain spaces even in quotes both for short and
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# long args, otherwise first word will return as value.
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# 6. You can use arg() or argl() to check presence of any arg, no matter
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# if it has value or not.
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### USAGE ###
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# This is simple examples which you can play around with.
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# first we must save the original arguments passed
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# to the script when it was called:
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MAIN_ARGS=$@
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echo -e "\n1. Short args (vars):"
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arg a 1 a # -a
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arg v 0 v # -v v_value
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arg c 1 c # -c
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arg z 1 z # -z (not exists)
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echo "1.1 a=$a"
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echo "1.2 v=$v"
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echo "1.3 c=$c"
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echo "1.4 z=$z"
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echo -e "\n2. Short args (echo):"
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echo "2.1 a=$(arg a 1)"
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echo "2.2 v=$(arg v 0)"
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echo "2.3 c=$(arg c 1)"
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echo "2.4 z=$(arg z 1)"
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echo -e "\n3. Long args (vars):"
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argl flag 1 flag # --flag
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argl param1 0 param1 # --param1=test
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argl param2 0 param2 # --param2=password
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argl bar 1 bar # --bar (not exists)
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echo "3.1 flag=$flag"
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echo "3.2 param1=$param1"
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echo "3.3 param2=$param2"
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echo "3.4 bar=$bar"
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echo -e "\n4. Long args (echo):"
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echo "4.1 flag=$(argl flag 1)"
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echo "4.2 param1=$(argl param1 0)"
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echo "4.3 param2=$(argl param2 0)"
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echo "4.4 bar=$(argl bar 1)"
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echo -e "\n5. Args by index:"
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argn 1 first
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echo "5.1 arg[1]=$first"
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echo "5.2 arg[3]=$(argn 3)"
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# Well, now we will try to get global args inside different functions
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food() {
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echo -e "\n=== food() ==="
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arg f 0 food
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argl 'food' 0 food
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[ $food ] && echo "Om nom nom! $food is very tasty" || echo "Uh oh" >&2
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}
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hello() {
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echo -e "\n=== hello() ==="
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arg n 0 name
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argl name 0 name
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[ $name ] && echo "Hi, $name! How u r doin?" || echo "Hello, stranger..." >&2
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}
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hello
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food
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### OUTPUT ###
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# Command to run:
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# bash args.sh -va asdf --flag --param1=paramvalue1 -c --param2="somevalue2 sdf" --name="John" -f Seafood
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# 1. Short args (vars):
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# 1.1 a=1
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# 1.2 v=v_value
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# 1.3 c=1
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# 1.4 z=
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#
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# 2. Short args (echo):
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# 2.1 a=1
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# 2.2 v=v_value
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# 2.3 c=1
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# 2.4 z=
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#
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# 3. Long args (vars):
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# 3.1 longflag=1
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# 3.2 param1=test
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# 3.3 param2=password
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# 3.4 barflag=
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#
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# 4. Long args (echo):
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# 4.1 longflag=1
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# 4.2 param1=test
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# 4.3 param2=password
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# 4.4 barflag=
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#
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# 5. Args by index:
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# 5.1 arg[1]=asdf
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# 5.2 arg[3]=--param1=paramvalue1
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#
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# === hello() ===
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# Hi, John! How u r doin?
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#
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# === food() ===
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# Om nom nom! Seafood is very tasty
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