第一部分 Shell基础编程——第六章 Shell函数

我就是我 2022-03-14 10:38 225阅读 0赞

### 笔记 ###

#Shell函数
    
    #函数定义
    [root@localhost 0416]# vi hellofun
    [root@localhost 0416]# cat hellofun
    #!/bin/bash
    #hellofun
    function hello()
    {
            echo "Hello,today is `date`"
            return 1
    }
    #无意义，不能执行
    [root@localhost 0416]# chmod 755 hellofun
    
    #函数调用
    #拷贝文件
    [root@localhost 0416]# cp hellofun func
    #编辑
    [root@localhost 0416]# vi func
    #查看
    [root@localhost 0416]# cat func
    #!/bin/bash
    #func
    function hello()
    {
            echo "Hello,today is `date`"
    }
    echo "now going to the function hello"
    hello
    echo "back from the function"
    #执行
    [root@localhost 0416]# ./func  
    now going to the function hello
    Hello,today is Tue Apr 16 15:30:43 CST 2013
    back from the function
    
    #参数传递
    #编辑
    [root@localhost 0416]# vi func2
    #查看
    [root@localhost 0416]# cat func2
    #!/bin/bash
    #func2
    function hello()
    {
    		#类似于位置参数
            echo "Hello,$1 today is `date`"
    }
    echo "now going to the function hello"
    hello chinaitlab
    echo "back from the function"
    #执行
    [root@localhost 0416]# ./func2
    now going to the function hello
    Hello,chinaitlab today is Tue Apr 16 15:34:21 CST 2013
    back from the function
    
    
    #函数文件
    #编辑
    [root@localhost 0416]# vi func3
    #查看
    [root@localhost 0416]# cat func3
    #!/bin/bash
    #func3
    #Source function
    #可以包含其他文件或者其他函数
    . hellofun
    echo "now going to the function hello"
    hello
    echo "back from the function"
    #执行
    [root@localhost 0416]# ./func3
    now going to the function hello
    Hello,today is Tue Apr 16 15:43:31 CST 2013
    back from the function
    #启动文件，学习Shell看启动文件，修改前注意备份
    #查看network文件
    [root@localhost root]# cat /etc/rc.d/init.d/network
    #查看functions文件
    [root@localhost root]# cat /etc/rc.d/init.d/ functions
    
    #检查载入函数和删除函数
    #拷贝文件
    [root@localhost 0416]# cp func3 func4
    #拷贝文件
    [root@localhost 0416]# cp func func4
    #查看文件
    [root@localhost 0416]# cat func4
    #!/bin/bash
    #func4
    #Source function
    . hellofun
    set
    echo "now going to the function hello"
    hello
    echo "back from the function"
    #执行
    [root@localhost 0416]# ./func4
    BASH=/bin/bash
    BASH_ENV=/root/.bashrc
    BASH_VERSINFO=([0]="2" [1]="05b" [2]="0" [3]="1" [4]="release" [5]="i386-redhat-linux-gnu")
    BASH_VERSION='2.05b.0(1)-release'
    CLASSPATH=.:/usr/java/jdk1.6.0_27/lib/dt.jar:/usr/java/jdk1.6.0_27/lib/tools.jar:/usr/java/jdk1.6.0_27/jre/lib/ext/mysql-connector-java-3.1.10-bin.jar
    DIRSTACK=()
    EUID=0
    GROUPS=()
    G_BROKEN_FILENAMES=1
    HISTSIZE=1000
    HOME=/root
    HOSTNAME=localhost.localdomain
    HOSTTYPE=i386
    IFS=$' \t\n'
    INPUTRC=/etc/inputrc
    JAVA_HOME=/usr/java/jdk1.6.0_27
    LAMHELPFILE=/etc/lam/lam-helpfile
    LANG=en_US.en
    LANGUAGE=zh_CN.GB18030:zh_CN.GB2312:zh_CN
    LESSOPEN='|/usr/bin/lesspipe.sh %s'
    LOGNAME=root
    LS_COLORS='no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:cd=40;33;01:or=01;05;37;41:mi=01;05;37;41:ex=01;32:*.cmd=01;32:*.exe=01;32:*.com=01;32:*.btm=01;32:*.bat=01;32:*.sh=01;32:*.csh=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*.tz=01;31:*.rpm=01;31:*.cpio=01;31:*.jpg=01;35:*.gif=01;35:*.bmp=01;35:*.xbm=01;35:*.xpm=01;35:*.png=01;35:*.tif=01;35:'
    MACHTYPE=i386-redhat-linux-gnu
    MAIL=/var/spool/mail/root
    OPTERR=1
    OPTIND=1
    OSTYPE=linux-gnu
    PATH=/usr/kerberos/sbin:/usr/kerberos/bin:/usr/java/jdk1.6.0_27/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/X11R6/bin:/root/bin
    PIPESTATUS=([0]="0")
    PPID=3541
    PS4='+ '
    PVM_ROOT=/usr/share/pvm3
    PVM_RSH=/usr/bin/rsh
    PWD=/home/wgb/shell/0416
    QTDIR=/usr/lib/qt-3.1
    SHELL=/bin/bash
    SHELLOPTS=braceexpand:hashall:interactive-comments
    SHLVL=2
    SSH_ASKPASS=/usr/libexec/openssh/gnome-ssh-askpass
    SSH_CLIENT='192.168.223.1 2757 22'
    SSH_CONNECTION='192.168.223.1 2757 192.168.223.100 22'
    SSH_TTY=/dev/pts/0
    TERM=vt100
    UID=0
    USER=root
    USERNAME=root
    XPVM_ROOT=/usr/share/pvm3/xpvm
    _=hellofun
    hello () 
    { 
        echo "Hello,today is `date`";
        return 1
    }
    now going to the function hello
    Hello,today is Tue Apr 16 17:54:50 CST 2013
    back from the function
    
    #查看文件
    [root@localhost 0416]# cat func5
    #!/bin/bash
    #func5
    #Source function
    . hellofun
    set
    unset hello
    echo "now going to the function hello"
    hello
    echo "back from the function"
    #执行
    [root@localhost 0416]# ./func5
    BASH=/bin/bash
    BASH_ENV=/root/.bashrc
    BASH_VERSINFO=([0]="2" [1]="05b" [2]="0" [3]="1" [4]="release" [5]="i386-redhat-linux-gnu")
    BASH_VERSION='2.05b.0(1)-release'
    CLASSPATH=.:/usr/java/jdk1.6.0_27/lib/dt.jar:/usr/java/jdk1.6.0_27/lib/tools.jar:/usr/java/jdk1.6.0_27/jre/lib/ext/mysql-connector-java-3.1.10-bin.jar
    DIRSTACK=()
    EUID=0
    GROUPS=()
    G_BROKEN_FILENAMES=1
    HISTSIZE=1000
    HOME=/root
    HOSTNAME=localhost.localdomain
    HOSTTYPE=i386
    IFS=$' \t\n'
    INPUTRC=/etc/inputrc
    JAVA_HOME=/usr/java/jdk1.6.0_27
    LAMHELPFILE=/etc/lam/lam-helpfile
    LANG=en_US.en
    LANGUAGE=zh_CN.GB18030:zh_CN.GB2312:zh_CN
    LESSOPEN='|/usr/bin/lesspipe.sh %s'
    LOGNAME=root
    LS_COLORS='no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:cd=40;33;01:or=01;05;37;41:mi=01;05;37;41:ex=01;32:*.cmd=01;32:*.exe=01;32:*.com=01;32:*.btm=01;32:*.bat=01;32:*.sh=01;32:*.csh=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*.tz=01;31:*.rpm=01;31:*.cpio=01;31:*.jpg=01;35:*.gif=01;35:*.bmp=01;35:*.xbm=01;35:*.xpm=01;35:*.png=01;35:*.tif=01;35:'
    MACHTYPE=i386-redhat-linux-gnu
    MAIL=/var/spool/mail/root
    OPTERR=1
    OPTIND=1
    OSTYPE=linux-gnu
    PATH=/usr/kerberos/sbin:/usr/kerberos/bin:/usr/java/jdk1.6.0_27/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/X11R6/bin:/root/bin
    PIPESTATUS=([0]="0")
    PPID=3541
    PS4='+ '
    PVM_ROOT=/usr/share/pvm3
    PVM_RSH=/usr/bin/rsh
    PWD=/home/wgb/shell/0416
    QTDIR=/usr/lib/qt-3.1
    SHELL=/bin/bash
    SHELLOPTS=braceexpand:hashall:interactive-comments
    SHLVL=2
    SSH_ASKPASS=/usr/libexec/openssh/gnome-ssh-askpass
    SSH_CLIENT='192.168.223.1 2757 22'
    SSH_CONNECTION='192.168.223.1 2757 192.168.223.100 22'
    SSH_TTY=/dev/pts/0
    TERM=vt100
    UID=0
    USER=root
    USERNAME=root
    XPVM_ROOT=/usr/share/pvm3/xpvm
    _=hellofun
    hello () 
    { 
        echo "Hello,today is `date`";
        return 1
    }
    now going to the function hello
    ./func5: line 8: hello: command not found
    back from the function
    #查看文件
    [root@localhost 0416]# cat func5
    #!/bin/bash
    #func5
    #Source function
    . hellofun
    #set
    unset hello
    echo "now going to the function hello"
    hello
    echo "back from the function"
    #执行
    [root@localhost 0416]# ./func5
    now going to the function hello
    ./func5: line 8: hello: command not found
    back from the function
    
    
    #函数返回状态值
    #拷贝文件
    [root@localhost 0416]# cp hellofun hellofunctions
    #查看文件
    [root@localhost 0416]# cat hellofunctions 
    #!/bin/bash
    #hellofunctions
    function hello()
    {
            echo "Hello,today is `date`"
            return 1
    }
    #拷贝文件
    [root@localhost 0416]# cp func func6
    #查看文件
    [root@localhost 0416]# cat func6
    #!/bin/bash
    #func6
    . hellofunctions
    echo "now going to the function hello"
    hello
    echo $?
    echo "back from the function"
    #返回0，正确执行，返回1，一般发生错误——约定
    #执行
    [root@localhost 0416]# ./func6
    now going to the function hello
    Hello,today is Tue Apr 16 18:02:56 CST 2013
    1
    back from the function
    #查看文件
    [root@localhost 0416]# cat hellofunctions 
    #!/bin/bash
    #hellofunctions
    function hello()
    {
            echo "Hello,today is `date`"
            return 0
    }
    #执行
    [root@localhost 0416]# ./func6
    now going to the function hello
    Hello,today is Tue Apr 16 18:02:56 CST 2013
    0
    back from the function
    #查看文件
    [root@localhost 0416]# cat func6
    #!/bin/bash
    #func6
    . hellofunctions
    echo "now going to the function hello"
    returnvalue=hello
    echo $?
    #这样的赋值是不允许的
    echo $returnvalue
    echo "back from the function"
    [root@localhost 0416]# ./func6
    now going to the function hello
    0
    hello
    back from the function
    #编辑文件
    [root@localhost 0416]# vi hellofunctions
    #查看文件
    [root@localhost 0416]# cat hellofunctions 
    #!/bin/bash
    #hellofunctions
    function hello()
    {
            echo "Hello,today is `date`"
            return 127
    }
    #执行文件，根据文件返回值就可以做一些操作
    [root@localhost 0416]# ./func6
    now going to the function hello
    127
    back from the function

### 附图 ###

![1366114577_8253.jpg][]

![1366114583_5364.jpg][]

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