{"id":2233,"date":"2019-08-20T08:58:11","date_gmt":"2019-08-20T06:58:11","guid":{"rendered":"http:\/\/les-fougs.com\/wordpress\/?p=2233"},"modified":"2019-08-20T14:04:12","modified_gmt":"2019-08-20T12:04:12","slug":"manipulation-de-chaine-de-caracteres-linux","status":"publish","type":"post","link":"http:\/\/les-fougs.com\/wordpress\/2019\/08\/20\/manipulation-de-chaine-de-caracteres-linux\/","title":{"rendered":"Manipulation de cha\u00eene de caract\u00e8res Linux"},"content":{"rendered":"
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Assigner et afficher une variable<\/h3>\n<\/div>\n<\/div>\n<\/div>\n

En BASH, une variable est identifi\u00e9e par l’usage du ‘$’, sauf pour lui attribuer une valeur o\u00f9 l’on omet le ‘$’.<\/p>\n

#assignation de la variable<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>maVariable='Ceci est une chaine de caract\u00e8res'<\/span>\r\n    \r\n#utilisation de la variable<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo $mavariable<\/span>\r\nCeci<\/span> est une chaine de caract\u00e8res<\/pre>\n
Il est \u00e9galement possible d’utiliser une syntaxe plus explicite qui permet de d\u00e9limiter clairement quel est le nom de la variable et d’\u00e9viter donc plus facilement des erreurs de nommage.<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>file='homework'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>ls \/mnt\/data\/$file_save<\/span>.doc<\/pre>\n
Dans cet exemple la variable utilis\u00e9e est ‘file_save’ et non ‘file’. Le r\u00e9sultat ne sera donc absolument pas celui qu’on attend !<\/p>\n
Une fa\u00e7on de d\u00e9limiter clairement le nom de la variable est d’utiliser les crochets ‘{}’.<\/p>\n
    96386<\/span>@kws<\/span>:~<\/span>$ <\/span>file='homework'<\/span>\r\n    96386<\/span>@kws<\/span>:~<\/span>$ <\/span>ls \/mnt\/data\/${<\/span>file}_save.doc<\/pre>\n
La variable utilis\u00e9e ici sera ‘file’ et a pour valeur ‘homework’. Ce qui donne donc la commande suivante une fois la variable substitu\u00e9e.<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>ls \/mnt\/data\/homework_save.doc<\/pre>\n
C’est cette syntaxe qui sera utilis\u00e9e tout au long de cet article.<\/p>\n<\/div>\n
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Modifier la casse<\/h3>\n<\/div>\n<\/div>\n<\/div>\n
Un des traitements les plus courants est de modifier la casse, que cela soit de passer tout en majuscule, ou en minuscule.<\/p>\n
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Tout passer en minuscule<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
Le changement de la casse en minuscule se fait \u00e0 l’aide de ‘,,’ comme ceci :<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>test=\"Hello World !\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo ${<\/span>test,,}\r\nhello world !<\/pre>\n<\/div>\n
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Tout passer en majuscule<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
Le changement de la casse en majuscule se fait \u00e0 l’aide de ‘^^’ comme ceci :<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>test=\"Hello World !\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo ${<\/span>test^^}\r\nHELLO<\/span> WORLD<\/span> !<\/pre>\n<\/div>\n
Ainsi un ‘case’ comme celui-ci<\/p>\n
case<\/span> ${userInput}<\/span> in<\/span>\r\n    \"oui\"<\/span>|\"Oui\"<\/span>|\"OUI\"<\/span>|\"O\"<\/span>|\"o\"<\/span>|\"YES\"<\/span>|\"Yes\"<\/span>|\"yes\"<\/span>|\"Y\"<\/span>|y\")\r\n        # action si l'utilisateur r\u00e9pond oui\r\n        ;;\r\n    \"<\/span>non\"|\"<\/span>Non\"|\"<\/span>NON\"|\"<\/span>NO|\"No\"<\/span>|\"no\"<\/span>|\"N\"<\/span>|\"n\"<\/span>)\r\n        # action si l'utilisateur r\u00e9pond non<\/span>\r\n        ;;\r\nesac<\/span>\r\n<\/pre>\n
devient simplement :<\/p>\n
case<\/span> ${userInput,,}<\/span> in<\/span>\r\n    \"oui\"<\/span>|\"yes\"<\/span>|\"y\"<\/span>|\"o\"<\/span>)\r\n        # action si l'utilisateur r\u00e9pond oui<\/span>\r\n    ;;\r\n    \"non\"<\/span>|\"no\"<\/span>|\"n\"<\/span>)\r\n        # action si l'utilisateur r\u00e9pond non<\/span>\r\n    ;;\r\nesac<\/span>\r\n<\/pre>\n<\/div>\n
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R\u00e9cup\u00e9rer la longueur de la chaine de caract\u00e8re.<\/h3>\n<\/div>\n<\/div>\n<\/div>\n
Pour r\u00e9cup\u00e9rer la longueur d’une chaine de caract\u00e8re il suffit de pr\u00e9c\u00e9der le nom de la variable par ‘#’ comme ceci :<\/p>\n
${#variable}<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"Chaine d'une certaine longueur\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo ${<\/span>#VAR}<\/span>\r\n30<\/span><\/pre>\n
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Taille d’un tableau<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
Il est possible d’obtenir le nombre d’\u00e9l\u00e9ments d’un tableau de la fa\u00e7on suivante :<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>unset VAR<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>[0<\/span>]=\"blablabla\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>[1<\/span>]=\"azeaze\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>[2<\/span>]=\"test\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>[3<\/span>]=\"someText\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>[4<\/span>]=48<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>[5<\/span>]=98985<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo ${<\/span>#VAR[*]}<\/span>\r\n6<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo ${<\/span>#VAR[@]}<\/span>\r\n6<\/span>\r\n<\/pre>\n
Attention \u00e0 ne pas oublier les crochets, sinon # retournera simplement la longueur du premier \u00e9l\u00e9ment du tableau.<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>unset VAR<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>[0<\/span>]=\"blablabla\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>[1<\/span>]=\"azeaze\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>[2<\/span>]=\"test\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo ${<\/span>#VAR}<\/span>\r\n9<\/span><\/pre>\n<\/div>\n
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D\u00e9terminer le nombre de param\u00e8tre pass\u00e9s au script<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
Pour connaitre le nombre de param\u00e8tres pass\u00e9s au script ($1, $2 …) on utilisera ‘${#*}’ et ‘${#@}<\/p>\n
96386<\/span>@kws:~$ vi test.sh\r\n#!\/bin\/bash<\/span>\r\necho<\/span> \"\\${#*} : '${#*}<\/span>' \\${#@} : '${#@}<\/span>'\"<\/span>\r\n    \r\n    \r\n96386<\/span>@kws:~$ bash test.sh var1 test<\/span> something\r\n${#*}<\/span> : '3'<\/span> ${#@}<\/span> : '3'<\/span><\/pre>\n<\/div>\n<\/div>\n
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Assignation des variables<\/h3>\n<\/div>\n<\/div>\n<\/div>\n
Plut\u00f4t que d’utiliser des ‘if’, ‘else’ et d’assigner des valeurs par d\u00e9faut si les variables sont vides il existe des m\u00e9canismes permettant l’usage ou l’assignation d’une valeur alternative pour ces variables.<\/p>\n
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Utiliser une alternative<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
La formulation ${var-alternative} permet l’utilisation d’une alternative si la variable n’est pas assign\u00e9e<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>unset VAR<\/span> # on s'assure que la variable n'existe pas\/plus<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"var: '${VAR-\"<\/span>default\"}'\"<\/span>\r\nvar:<\/span> 'default'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"var: '${VAR-\"<\/span>default\"}'\"<\/span>\r\nvar:<\/span> ''<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"VALUE\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"var: '${VAR-\"<\/span>default\"}'\r\nvar: 'VALUE'\r\n\r\n96386@kws:~$ VAR2=\"<\/span>someVar\"\r\n96386@kws:~$ unset VAR\r\n96386@kws:~$ echo ${VAR-$VAR2}\r\nsomeVar<\/span><\/pre>\n
On constate que si la variable existe mais ne contient aucun caract\u00e8re, elle n’est pas remplac\u00e9e par la valeur de substitution. Pour sp\u00e9cifier \u00e0 Bash que les variables vides sont \u00e9galement \u00e0 remplacer nous allons utiliser la forme suivante : ${var:-alternative} (ajout du ‘:’).<\/p>\n
96386<\/span>@kws<\/span>:~$ unset VAR # on s'assure que la variable n'existe pas\/plus<\/span>\r\n96386<\/span>@kws<\/span>:~$ echo \"'${VAR:-\"default\"}<\/span>'\"<\/span>\r\n'default'<\/span>\r\n96386<\/span>@kws<\/span>:~$ VAR=\"\"<\/span>\r\n96386<\/span>@kws<\/span>:~$ echo \"'${VAR:-\"default\"}<\/span>'\r\n'default'\r\n96386@kws<\/span>:~$ VAR=\"<\/span>VALUE\"\r\n96386@kws<\/span>:~$ echo \"<\/span>'${VAR:-\"default\"}'<\/span>\"\r\n'VALUE' \r\n96386@kws<\/span>:~$ VAR2=\"<\/span>someVar\"\r\n96386@kws<\/span>:~$ VAR=\"<\/span>\"\r\n96386@kws<\/span>:~$ echo ${VAR:-$VAR2<\/span>}<\/span>\r\nsomeVar<\/span><\/pre>\n<\/div>\n
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Assigner une valeur par d\u00e9faut<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
La m\u00e9thode pr\u00e9c\u00e9dente permettait de retourner une valeur diff\u00e9rente lors de l’usage de la variable mais la valeur de la variable restait inchang\u00e9e. La syntaxe ${var= »alternativeValue »} permet de d’assigner une valeur \u00e0 la variable si celle ci n’est pas d\u00e9clar\u00e9e .<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>unset VAR<\/span> # on s'assure que la variable n'existe pas\/plus<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"var :'$VAR'\"<\/span>\r\nvar :''<\/span><\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"var :'${VAR=default}'\"<\/span>\r\nvar :'default'<\/span><\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"var :'$VAR'\"<\/span>\r\nvar :'default'<\/span><\/span>\r\n<\/pre>\n
Comme pour l’utilisation d’une valeur de substitution, il est possible de diff\u00e9rencier une variable non assign\u00e9e d’une variable vide. ${VAR:=default} permet de remplacer la valeur des variables d\u00e9clar\u00e9e mais vides.<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"var :'$VAR'\"<\/span>\r\nvar :''<\/span><\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"var :'${VAR=default}'\"<\/span>\r\nvar :''<\/span><\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"var :'$VAR'\"<\/span>\r\nvar :''<\/span><\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"var :'${VAR:=default}'\"<\/span>\r\nvar :'default'<\/span><\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"var :'$VAR'\"<\/span>\r\nvar :'default'<\/span><\/span><\/pre>\n<\/div>\n
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Utiliser une alternative et quitter<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
Toujours dans la liste des valeurs alternatives, il est possible d’utiliser une valeur par d\u00e9faut et de quitter le programme avec un code de de retour ‘1’. La formulation est la suivante : ${var?alternative]<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>unset var\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>parametre=${<\/span>VAR<\/span>?\"Var is not set\"<\/span>}\r\nbash:<\/span> VAR<\/span>:<\/span> Var<\/span> is not<\/span> set<\/pre>\n
La formulation reste la m\u00eame pour sp\u00e9cifier que l’on souhaite aussi filtrer les variables d\u00e9finies mais vides : ${var:? »Var is not set or empty »}<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>var=\"\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>parametre=${<\/span>VAR<\/span>:?\"<\/span>Var<\/span> is not<\/span> set or<\/span> empty\"}\r\n-bash: var: Var is not set or empty<\/span><\/pre>\n<\/div>\n<\/div>\n
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Extraire une sous-chaine<\/h3>\n<\/div>\n<\/div>\n<\/div>\n
Il est courant de travailler sur des fractions d’une chaine de caract\u00e8res. Il est possible d’obtenir ses \u00e9l\u00e9ments avec la fonction suivante : ${var:<position>:<longueur>}<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"Hello world !\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR:6}'\"<\/span>\r\n'world !'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR:1:4}'\"<\/span>\r\n'ello'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR:6:20}'\"<\/span>\r\n'world !'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR::3}'\"<\/span>\r\n'first 3'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR: -3}'\"<\/span>\r\n'd !'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR::-1}'\"<\/span>\r\n'Hello world '<\/span><\/pre>\n<\/div>\n
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Supprimer une sous-chaine<\/h3>\n<\/div>\n<\/div>\n<\/div>\n
Il est possible de se d\u00e9barrasser rapidement de chaine de caract\u00e8res pr\u00e9c\u00e9dant ou suivant la partie recherch\u00e9e, pour r\u00e9cup\u00e9rer le nom d’un fichier sans les r\u00e9pertoires auquel il appartient ou sans son extension par exemple !<\/p>\n
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‘#’ Supprimer depuis le d\u00e9but de la chaine<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
L’utilisation du ‘#’ (${var#pattern}) permet de supprimer la premi\u00e8re portion correspondant au pattern que l’on passe en param\u00e8tre.<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"hello world !\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR#h*o}'\"<\/span>\r\n' world !'<\/span>.<\/pre>\n<\/div>\n
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##<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
Le double ‘#’ (${var##pattern) s’utilise de la m\u00eame fa\u00e7on que le simple ‘#’ \u00e0 la diff\u00e9rence que celui-ci supprimera la chaine correspondante la plus longue.<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"hello world !\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR##h*o}'\"<\/span>\r\n'rld !'<\/span><\/pre>\n<\/div>\n
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‘%’ Supprimer depuis la fin de la chaine<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
Le ‘%’ (${var%pattern}) permet de supprimer la chaine correspondante \u00e0 notre pattern depuis la fin de notre variable<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"hello world !\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR%o*}'\"<\/span>\r\n'hello w'<\/span><\/pre>\n<\/div>\n
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%%<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
Comme pour le ‘##’ le double %% permet de s\u00e9lectionner la plus grande chaine, ici depuis la fin de la variable.<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"hello world !\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR%%o*}'\"<\/span>\r\n'hell'<\/span><\/pre>\n<\/div>\n
A noter que ces outils ne permettent la suppression de chaine de caract\u00e8res que depuis l’un des bords de la variable.<\/p>\n
Pour supprimer une sous-chaine pr\u00e9sente au milieu de la variable on pourra utiliser de remplacement de chaine de caract\u00e8re ‘\/’ sans lui passer de chaine de remplacement. Pour supprimer la premi\u00e8re occurence :<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"hello world !\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR\/o\/}'\"<\/span>\r\n'hell world !'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"hello world !\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR\/l*o\/}'\"<\/span>\r\n'herld !'<\/span>\r\n<\/pre>\n
Pour supprimer l’ensemble des occurrences on utilisera ‘\/\/’<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"hello world !\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR\/\/o\/}'\"<\/span>\r\n'hell wrld !'<\/span><\/pre>\n
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Exemple d’utilisation<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
Les traitements de chaines de caract\u00e8re que nous voulons voir sont tr\u00e8s pratiques lorsque, par exemple, de la manipulation de fichiers. Prenons ici comme exemple le fichier ‘\/etc\/apache2\/sites-available\/000-default.conf’ et regardons ensemble comment extraire le path, le nom du fichier et son extension.<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>file='\/etc\/apache2\/sites-available\/000-default.conf'<\/span><\/pre>\n
Pour r\u00e9cup\u00e9rer le path, nous allons simplement tout supprimer depuis la fin du fichier jusqu’au premier ‘\/’ rencontr\u00e9<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>file='\/etc\/apache2\/sites-available\/000-default.conf'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>filePath=${<\/span>file%\/*}\r\n96386@kws:~$ echo $filePath \r\n\/<\/span>etc\/apache2\/sites-available<\/pre>\n
Pour r\u00e9cup\u00e9rer le fichier, nous allons proc\u00e9der de la fa\u00e7on inverse : nous allons tout supprimer depuis le d\u00e9but jusqu’au dernier ‘\/’<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>file='\/etc\/apache2\/sites-available\/000-default.conf'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>fileName=${<\/span>file##*\/}<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo $fileName<\/span> \r\n000<\/span>-default.conf<\/pre>\n
Pour supprimer l’extension de notre fichier nous allons supprimer tout les caract\u00e8res depuis la fin jusqu’au premier ‘.’<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>file='\/etc\/apache2\/sites-available\/000-default.conf'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>fileNameShort=${<\/span>fileName%.*}\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo $fileNameShort<\/span> \r\n000<\/span>-default<\/pre>\n
Et enfin pour extraire l’extension nous allons garder uniquement ce qu’il reste apr\u00e8s le dernier ‘.’<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>file='\/etc\/apache2\/sites-available\/000-default.conf'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>fileExtension=${<\/span>fileName##*.}<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo $fileExtension<\/span> \r\nconf<\/pre>\n<\/div>\n<\/div>\n
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Remplacement de sous-chaine<\/h3>\n<\/div>\n<\/div>\n<\/div>\n
En plus des possibilit\u00e9s de suppression et d’extraction de sous-chaine de caract\u00e8re, il est \u00e9galement possible de remplacer certaines expressions dans notre variable avec l’utilisation du ‘\/’.<\/p>\n
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Remplacer le premier \u00e9l\u00e9ment trouv\u00e9.<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
Pour remplacer le premi\u00e8re \u00e9l\u00e9ment correspondant, on utilisera la syntaxe suivante :${var\/pattern\/remplacement\/}.<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"blablabla\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR\/a\/o}'\"<\/span>\r\n'bloblabla'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR\/bl\/pl}'\"<\/span>\r\n'pliblablobleblu'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR\/bla\/123}'\"<\/span>\r\n'bli123blobleblu'<\/span><\/pre>\n<\/div>\n
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Remplacer l’ensemble des \u00e9l\u00e9ments correspondants.<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
Pour remplacer l’ensemble des \u00e9l\u00e9ments correspondants par la chaine pass\u00e9 en deuxi\u00e8me param\u00e8tre nous utiliserons le double ‘\/’.<\/p>\n
${string\/\/substring\/replacement}<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"blablabla\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR\/\/a\/o}'\"<\/span>\r\n'blobloblo'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>VAR<\/span>=\"bliblablobleblu\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR\/\/bl\/pl}'\"<\/span>\r\n'pliplaplopleplu'<\/span>\r\n<\/pre>\n<\/div>\n
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Remplacer le dernier \u00e9l\u00e9ment correspondant.<\/h4>\n<\/div>\n<\/div>\n<\/div>\n
Pour remplacer la plus grande correspondance depuis le d\u00e9but de la chaine on utilisera le ‘\/#’<\/p>\n
${string\/#substring\/replacement}<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>var=\"Hello, world !\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${var\/#*o\/i}'\"<\/span>\r\n'irld !'<\/span><\/pre>\n
Ce qui est similaire \u00e0 ‘\/’<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR\/*o\/i}'\"<\/span>\r\n'irld !'<\/span><\/pre>\n
Pour remplacer la plus longue correspondance depuis la fin de la chaine de caract\u00e8re, on utilisera le ‘\/%’<\/p>\n
${string\/%substring\/replacement}<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>var=\"Hello, world !\"<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${var\/%o\/i}'\"<\/span>\r\n'Hello, world !'<\/span>\r\n96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${var\/%o*\/il}'\"<\/span>\r\n'Helli'<\/span><\/pre>\n
Ce qui est similaire \u00e0 ‘\/’<\/p>\n
96386<\/span>@kws<\/span>:~<\/span>$ <\/span>echo \"'${VAR\/o*\/i}'\"<\/span>\r\n'irld !'<\/span><\/pre>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
Assigner et afficher une variable En BASH, une variable est identifi\u00e9e par l’usage du ‘$’, sauf pour lui attribuer une valeur o\u00f9 l’on omet le ‘$’. #assignation de la variable 96386@kws:~$ maVariable=’Ceci est une chaine de caract\u00e8res’ #utilisation de la variable 96386@kws:~$ echo $mavariable Ceci est une chaine de caract\u00e8res Il est \u00e9galement possible d’utiliser … Continuer la lecture de « Manipulation de cha\u00eene de caract\u00e8res Linux »<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[53],"tags":[],"_links":{"self":[{"href":"http:\/\/les-fougs.com\/wordpress\/wp-json\/wp\/v2\/posts\/2233"}],"collection":[{"href":"http:\/\/les-fougs.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/les-fougs.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/les-fougs.com\/wordpress\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/les-fougs.com\/wordpress\/wp-json\/wp\/v2\/comments?post=2233"}],"version-history":[{"count":3,"href":"http:\/\/les-fougs.com\/wordpress\/wp-json\/wp\/v2\/posts\/2233\/revisions"}],"predecessor-version":[{"id":2236,"href":"http:\/\/les-fougs.com\/wordpress\/wp-json\/wp\/v2\/posts\/2233\/revisions\/2236"}],"wp:attachment":[{"href":"http:\/\/les-fougs.com\/wordpress\/wp-json\/wp\/v2\/media?parent=2233"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/les-fougs.com\/wordpress\/wp-json\/wp\/v2\/categories?post=2233"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/les-fougs.com\/wordpress\/wp-json\/wp\/v2\/tags?post=2233"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}