BASH > les arguments

TESTER LE NOMBRE D’ARGUMENTS

$#donne le nombre d’arguments.

Exemple : ./test.sh toto tata renvoie 2




 

if [ $# -ne 0 ] ; then
   // blabla
fi

VALEUR D’UN ARGUMENT

$0 renvoie le nom du script.

$1 retourne la valeur du premier argument, $2 pour le deuxième, etc.

 

./test.sh toto tata
$0 -> test.sh
$1 -> toto
$2 -> tata

Accéder au 10ème argument

script.sh un deux trois quatre cinq six sept huit neuf dix onze
echo $10 → un0
echo ${10} → dix

TOUS LES ARGUMENTS

"$*" considère l’ensemble des paramètres comme une unique chaîne de caractères "$1 $2 … "

"$@" produit autant de chaînes que de paramètres "$1″ "$2″ …

 

DÉCALER LES ARGUMENTS

shift N décale N fois la position des paramètres. Par défaut, N = 1

Une fois le décalage effectué, le paramètre # est mis à jour.

 

script.sh toto tata titi
echo $1 → toto
shift
echo $1 → tata

 

script.sh toto tata titi
echo $1 → toto
shift 2
echo $1 → titi

PARAMÈTRE PAR DÉFAUT

Si on ne donne pas de paramètre à un script alors qu’il en faut un :

Donner une valeur par défaut au 1er paramètre : : ${1:=toto}

Afficher un message d’erreur : : ${1:?"Erreur: argument manquant"}

Passer des arguments nommés

mon_script.sh -p_out '/some/path' -arg_1 '5'

 

#!/bin/bash

while getopts ":a:p:" opt; do
  case $opt in
    a) arg_1="$OPTARG"
    ;;
    p) p_out="$OPTARG"
    ;;
    \?) echo "Option non valide: -$OPTARG" >&2
    exit 1
    ;;
  esac
  case $OPTARG in
    -*) echo "L'option $opt doit avoir une valeur"
    exit 1
    ;;
  esac
done

printf "Argument p_out is %s\n" "$p_out"
printf "Argument arg_1 is %s\n" "$arg_1"

Then you can do

$ ./my_script -p '/some/path' -a5
Argument p_out is /some/path
Argument arg_1 is 5

 

Voir Small getopts tutorial or you can type help getopts at the shell prompt.

 

This is not a parser for positioned arguments, is for key=value aa=bb arguments;

for ARG in "$@" ; do
   KEY=$(echo $ARG | cut -f1 -d=)
   KEY_LENGTH=${#KEY}
   VALUE="${ARG:$KEY_LENGTH+1}"
   export "$KEY"="$VALUE"
done
# use here your expected variables
echo "STEPS = $STEPS"
echo "REPOSITORY_NAME = $REPOSITORY_NAME"
echo "EXTRA_VALUES = $EXTRA_VALUES"

 

Usage

bash args_shell_parser.sh STEPS="ABC" REPOSITORY_NAME="stackexchange" EXTRA_VALUES="KEY1=VALUE1 KEY2=VALUE2"

 

Console result:

STEPS = ABC
REPOSITORY_NAME = stackexchange
EXTRA_VALUES = KEY1=VALUE1 KEY2=VALUE2

 

Features:

>values could have spaces.

>It handles complex cases, when the argument value contains "=" sign

 

I stole this from drupal.org, but you could do something like this:

while [ $# -gt 0 ]; do
  case "$1" in
    --p_out=*) p_out="${1#*=}"
               ;;
    --arg_1=*) arg_1="${1#*=}"
               ;;
    *) printf "*** Error: Invalid argument. ***\n"
       exit 1
  esac
  shift
done

 

The probably closest syntax to that is:

p_out='/some/path' arg_1='5' my_script

 

I just came up with this script

while [ $# -gt 0 ]; do
   if [[ $1 == *"--"* ]]; then
      v="${1/--/}"
      declare $v="$2"
   fi
   shift
done

 

pass it like my_script --p_out /some/path --arg_1 5 and then in the script you can use $arg_1 and $p_out.

 

This answer was initially an edit of @cdmo’s answer (thanks to @Milkncookiez’s comment also!), that got rejected as expected.

When using the variables, one can make sure that they have a default value set by using "${p_out:-"default value"}" for example.

 

From 3.5.3 Shell Parameter Expansion of the GNU Bash manual:
${parameter:-word}

 

If parameter is unset or null, the expansion of word is substituted. Otherwise, the value of parameter is substituted.

#!/bin/bash
while [ $# -gt 0 ]; do
  case "$1" in
    -p|-p_out|--p_out)      p_out="$2"
              ;;
    -a|-arg_1|--arg_1)      arg_1="$2"
      ;;
    *) printf "*** Error: Invalid argument. ***\n"
       exit 1
  esac
  shift
  shift
done
echo "--- Sans default values ---"
echo "p_out: ${p_out}"
echo "arg_1: ${arg_1}"
echo "--- Avec default values:"
echo "p_out: ${p_out:-\"27\"}"
echo "arg_1: ${arg_1:-\"smarties cereal\"}"

 

The below invocations are all equivalent:

$ ./my-script.sh -a "lofa" -p "miez"
$ ./my-script.sh -arg_1 "lofa" --p_out "miez"
$ ./my-script.sh --arg_1 "lofa" -p "miez"

 

I found the solution from cdmo the best, because it is not only limited to a single letter. With a slight adjustment it will consume either whitespace separated arguments like --url www.example.com and those with an assignment like, for example the synonym parameter -u=www.example.com. Even flag arguments can be parsed:

while [ $# -gt 0 ]; do
  case "$1" in
    --url*|-u*)      if [[ "$1" != *=* ]]; then shift; fi # Value is next arg if no `=`
                     URL="${1#*=}"
      ;;
    --file*|-f*)     if [[ "$1" != *=* ]]; then shift; fi
                     FILE="${1#*=}"
      ;;
    --help|-h)       printf "Meaningful help message" # Flag argument
                     exit 0
      ;;
    *)               >&2 printf "Error: Invalid argument\n"
                     exit 1
      ;;
  esac
  shift
done

 

I made a combination of some approaches recommended here. In my case, I need a script that could handle arguments in this format: --arg1=test So I used the following:

args=()

for argument in "$@"
do

    key=$(echo $argument | cut -f1 -d=)
    value=$(echo $argument | cut -f2 -d=)   

    if [[ $key == *"--"* ]]; then
        v="${key/--/}"
        declare $v="${value}"
   fi
done

args+=( '--local_dir' ${local_dir})
args+=( '--format' ${format})

python3 ./test.py "${args[@]}"

 

You can see that I added the arguments together to call a python script with those arguments: test_script.sh --local_dir=test --format=other

Thanks to Shahzad Malik and JRichardsz, for the guide to join the two approaches.

I have just made this one. It doesn’t require "=" and supports non-valued parameters. Mind the need of additional shift commands for valued parameters.

#!/bin/bash

if [ $# -eq 0 ]; then
    printf "Utilizacao:\n"
    printf "$0 [[--imagem_inicial|-i] <tag_inicial>] [[--imagem_final|-f] <tag_final>] [--verbose|-v]\n"
    exit 1
fi

while [ $# -gt 0 ]; do
  case "$1" in
    --imagem_inicial|-i)
      export tag_imagem_inicial="${2}"
      shift
      ;;
    --imagem_final|-f)
      export tag_imagem_final="${2}"
      shift
      ;;
    --verbose|-v)
      export verbose_option=1
      ;;
    *)
      printf "ERRO: Parametros invalidos\n"
      printf "Execute sem parametros para a sintaxe.\n"
      exit 1
  esac
  shift
done

echo tag_imagem_inicial=${tag_imagem_inicial}
echo tag_imagem_final=${tag_imagem_final}

 

My solution is based on that of JRichardsz, but fixing a few issues and adding more transparency about what’s actually going on − I’m not a fan of "copy this random code that you don’t understand, and run it on your personal computer. I swear it’s safe" :P

for argument in "$@"
do
  key=$(echo $argument | cut --fields 1 --delimiter='=')
  value=$(echo $argument | cut --fields 2 --delimiter='=')

  case "$key" in
    "wallet")        wallet="$value" ;;
    "network")       network="$value" ;;
    *)
  esac
done

echo "We'll be using wallet $wallet and network $network"

 

Invoking this script can be done as:

myScript.sh wallet=myWallet.json network=https://granadanet.smartpy.io

—

EXEMPLE DE SCRIPT

copier un fichier / dossier

 

#!/bin/bash
for argument in "$@" ; do
   key=$(echo $argument | cut --fields 1 --delimiter='=')
   value=$(echo $argument | cut --fields 2 --delimiter='=')
   case "$key" in
      "d") d="$value" ;; # directory
      "b") b="$value" ;; # basename
      "w") w="$value" ;; # basename without extension
      "x") x="$value" ;; # extension
      *)
   esac
done

# Switch Directory
cd "$d"

# Determine Extension
if [[ -z "$x" ]] ; then
   extn=$null
else
   extn=".$x"
fi

# Determine Copy Count
n=1
out="$w-copy$n$extn"
while [ -e "$out" ]; do
   n=$(( n + 1 ))
   out="$w-copy$n$extn"
done

# Construct Command
if [ -d "$b" ] ; then
   command=(/usr/bin/rsync -ar "$b/" "$out")
else
   command=(/usr/bin/rsync -a "$b" "$out")
fi

# DEBUG: Display Command
#zenity --info --text="${command[*]//"/\\"/}" --width=600
# Execute Command
"${command[@]}"
# Handle Command Error
res=$?
if [[ $res != 0 ]] ; then
   zenity --error --text="Duplication of $b failed (not root?)\n- base: $b\n- ext: $x\n- dir: $d" --width=600
fi

 

—