常用shell小脚本

 

1. Usage函数
   

   function Usage() {
       cat <<-delimiter
       Usage: command [-x] [-v] [-z] [files]
       A short explanation of the operation goese here
       It might be a few lines long, but shoudn't be excessive
       delimiter
   }

    

2. 转换字符
   

   tr a-z A-Z <<delimiter
   Working directory $PWD
       uio
           bnm
   delimiter    

    

3. 重复字符串
   

   b=uiop
   v=$(printf "%-10s" $b)
   echo "${v// /$b}"
   
   
   printf "%.s$b" {1..10}

    

4. 转换秒 => hour minute second
   

   function swap_seconds() {
       if [ "$1" -lt 60 ];then
           echo "full backup lasts $1 seconds"
       elif [ "$1" -lt 3600 ];then
           echo "full backup lasts $[$1/60] minutes $[$1%60] seconds"
       elif [ "$1" -lt 86400 ];then
           echo "full backup lasts $[$1/3600] hours $(($1%3600/60)) minutes $[$1%60] seconds"
       else
           echo 'full backup took too much time!'
       fi
   }
   
   swap_seconds $1

    

   function convert_seconds() {
           local T=$1
           local D=$((T/60/60/24))
           local H=$((T/60/60%24))
           local M=$((T/60%60))
           local S=$((T%60))
   
           (($D > 0)) && printf ' %d days' $D
           (($H > 0)) && printf ' %d hours' $H
           (($M > 0)) && printf ' %d minutes' $M
           ((($D > 0 || $H > 0 || $M > 0) && $S != 0)) && printf ' and '
           (($S > 0 )) && printf '%d seconds\n' $S
   }
   
   convert_seconds $1

    

5. # encapsulation 
   function checkCommandExists() {
     local cmd="$1"
     if [ -z "$cmd" ]; then
       echo "Usage: checkCommandExists command"
       return 1
     fi
     which "$cmd" >/dev/null 2>&1
     if [ $? -eq 0 ]; then
       return 0
     fi
     return 5
   }
   
   function installPackages() {
     zypper --quiet refresh --force
     for package in "$@"; do
       if ! rpm --verify --quiet "$package"; then
         if ! zypper --quiet --no-gpg-checks install -y "$package"; then
           echo -e "\e[31;5;7mpackage $package installation failed!!!\e[0m"
           exit 5
         fi
       fi
     done
   }
   
   # check docker existence
   checkCommandExists docker || { echo -e '\033[7mdocker is not installed!\033[0m' && exit 5; }
   
   # prerequisites, to install additional software, just add to this array.
   declare -a packages=(
     readline-devel
     libopenssl-devel
     libxslt-devel
     libxml2-devel
     unixODBC-devel
     netcat-openbsd
     libseccomp2
   )
   
   # install prequisites
   installPackages "${packages[@]}"