shell脚本备忘

#!/usr/bin/bash
echo "hello world"
#for 循环和C一样
for ((i=1; i<11; i++))
  do
   if ((i<10)); then
     #变量赋值，等号前后没有空格
     tsk=test_0$i
   else
     tsk=test_$i
   fi
     #打印当前值
     echo $tsk
    #判断目录是否存在
    if [ -d $tsk ]; then
      rm  -rf $tsk
      echo "$tsk is exist, will delete and create new"
      mkdir $tsk
    else
      mkdir $tsk
      echo "$tsk is not exist, it will be created"
    fi
    #shell copy当前文件到新目录
    cp a b c d $tsk
    #shell进入新目录
    cd $tsk
    #shell sed替换xxx
    sed -i "s/xxx/$tsk/g" d
    #shell返回上次目录
    cd -
  done