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Page last modified 17:08, 3 Feb 2020 by alang

SHELL開發時常用函數

    版本為 22:40, 20 Nov 2024

    到這個版本。

    返回到 版本存檔.

    查閱目前版本

    函數開發技巧與一些很實用的函數範例

    ip 驗證

    # Test an IP address for validity:
# Usage:
#      valid_ip IP_ADDRESS
#      if [[ $? -eq 0 ]]; then echo good; else echo bad; fi
#   OR
#      if valid_ip IP_ADDRESS; then echo good; else echo bad; fi
#
function is_ip()
{
    local  ip=$1
    local  stat=1

    if [[ $ip =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
        OIFS=$IFS
        IFS='.'
        ip=($ip)
        IFS=$OIFS
        [[ ${ip[0]} -le 255 && ${ip[1]} -le 255 \
            && ${ip[2]} -le 255 && ${ip[3]} -le 255 ]]
        stat=$?
    fi
    return $stat
}

    分割線(自動調整寬度)

    CL () { 
WORDS=$@; termwidth="$(tput cols)"; padding="$(printf '%0.1s' ={1..500})"; printf '%*.*s %s %*.*s\n' 0 "$(((termwidth-2-${#WORDS})/2))" "$padding" "$WORDS" 0 "$(((termwidth-1-${#WORDS})/2))" "$padding"; 
}

CL "This is Seperator Line"

    大小寫轉換

    ToUpper() {
    echo $1 | tr "[:lower:]" "[:upper:]"
}

ToLower() {
    echo $1 tr "[:upper:]"} "[:lower:]"
}

    URL 字串編碼

    function urlencode() {
    local data
    if [[ $# != 1 ]]; then
        echo "Error: No string to urlencode"
        return 1
    fi
    data="$(curl -s -o /dev/null -w %{url_effective} --get --data-urlencode "$1" "")"
    if [[ $? != 3 ]]; then
        echo "Unexpected error" 1>&2
    else
        echo "${data##/?}"
    fi
    return 0
}

urlencode "$1"

function urldecode() {
    # urldecode <string>

    local url_encoded="${1//+/ }"
    printf '%b' "${url_encoded//%/\\x}"
}

    函數回傳字串

    Example-1: Using Global Variable

    function F1()
{
    retval='I like programming'
}

retval='I hate programming'
echo $retval
F1
echo $retval

    Example-2: Using Function Command

    function F2()
{
    local  retval='Using BASH Function'
    echo "$retval"
}

getval=$(F2)   
echo $getval

    Example-3: Using Variable

    function F3()
{
    local arg1=$1
    
    if [[ $arg1 != "" ]]; 
    then
        retval="BASH function with variable"
    else
        echo "No Argument"
    fi
}

getval1="Bash Function"
F3 $getval1
echo $retval
getval2=$(F3)
echo $getval2

    is_root

    用途：檢查是否以 root 帳號執行

    reference to undefined name 'syntax' Exception of type 'MindTouch.Deki.Script.Runtime.DekiScriptUndefinedNameException' was thrown. (click for details)

    check_os

    用途：檢查 OS 版本

    reference to undefined name 'syntax' Exception of type 'MindTouch.Deki.Script.Runtime.DekiScriptUndefinedNameException' was thrown. (click for details)

    Check_Myself

    用途：檢查自身程序是否已經執行中，如果有，程序立即跳離，可避免同一個 script 重複被執行。

    reference to undefined name 'syntax' Exception of type 'MindTouch.Deki.Script.Runtime.DekiScriptUndefinedNameException' was thrown. (click for details)

    getopts 指令參數

    reference to undefined name 'syntax' Exception of type 'MindTouch.Deki.Script.Runtime.DekiScriptUndefinedNameException' was thrown. (click for details)

    Pause 暫停

    用法: pause

    可用於程式開發及偵錯

    reference to undefined name 'syntax' Exception of type 'MindTouch.Deki.Script.Runtime.DekiScriptUndefinedNameException' was thrown. (click for details)

    Log 訊息

    log() {  # classic logger
    local prefix="[$(date +%Y/%m/%d\ %H:%M:%S)]: "
    echo "${prefix} $@" >&2
} 

log "INFO" "a message"

    Error 錯誤訊息

    用途：輸出錯誤訊息

    reference to undefined name 'syntax' Exception of type 'MindTouch.Deki.Script.Runtime.DekiScriptUndefinedNameException' was thrown. (click for details)
    reference to undefined name 'syntax' Exception of type 'MindTouch.Deki.Script.Runtime.DekiScriptUndefinedNameException' was thrown. (click for details)

    詢問 Yes/No

    用法: getyn "Would you like to install WANPIPE now? [y]"

    $NONINTERACTIVE  如果程式執行時，不想讓 user 做任何的輸入時，可以為 1
    NONINTERACTIVE=1 ，或者 = 空白，以顯示相關的提示訊息

    reference to undefined name 'syntax' Exception of type 'MindTouch.Deki.Script.Runtime.DekiScriptUndefinedNameException' was thrown. (click for details)
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