shell 脚本技巧

1、Give ECHO colors see see!

NORMAL=$(tput sgr0)
GREEN=$(tput setaf ; tput bold)
YELLOW=$(tput setaf )
RED=$(tput setaf )

function red() {
    echo -e "$RED$*$NORMAL"
}

function green() {
    echo -e "$GREEN$*$NORMAL"
}

function yellow() {
    echo -e "$YELLOW$*$NORMAL"
}

# To print success
green "Task has been completed"

# To print error
red "The configuration file does not exist"

# To print warning
yellow "You have to use higher version."

关于上面这个，我个人感觉不是很好，还有别的方法，以后再说吧！

2、打印 Debug 信息

function debug() {
    if [[ $DEBUG ]]
    then
        echo ">>> $*"
    fi
}

# For any debug message
debug "Trying to find config file"

合并成一行：

# From cool geeks at hacker news
function debug() { ((DEBUG)) && echo ">>> $*"; }
function debug() { [ "$DEBUG" ] && echo ">>> $*"; }

3、检查可执行文件是否存在：

OK=
FAIL=

function require_curl() {
    which curl &>/dev/null
    if [ $? -eq  ]
    then
      return $OK
    fi

    return $FAIL
}

其实也就一行就可以解决:function require_curl() {which culr &>/dev/null;}

4、打印命令的使用方式：

cat << EOF

Usage: myscript <command> <arguments>

VERSION: 1.0

Available Commands

    install - Install package

    uninstall - Uninstall package

    update - Update package

    list - List packages

EOF

5、给变量加默认值：

URL=${URL:-http://localhost:8080}

6、检查字符串变量的长度：

if [ ${#authy_api_key} !=  ]
then
  red "you have entered a wrong API key"
  return $FAIL
fi

7、半延迟读取数据：

READ_TIMEOUT=
read -t "$READ_TIMEOUT" input

# if you do not want quotes, then escape it
input=$(sed "s/[;\`\"\$\' ]//g" <<< $input)

# For reading number, then you can escape other characters
input=$(sed 's/[^0-9]*//g' <<< $input)

8、获取目录和文件的名称：

# To find base directory
APP_ROOT=`dirname "$0"`

# To find the file name
filename=`basename "$filepath"`

# To find the file name without extension
filename=`basename "$filepath" .html`

此文出自老外，觉得挺好，就译了过来！不算盗版吧，哈哈！

学一点，收获一点。学到的都是自己的！