shell编程笔记三:流程控制
格式:
if ....; then .... elif ....; then .... else .... fi
- [ -f "somefile" ] :判断是否是一个文件
- [ -x "/bin/ls" ] :判断/bin/ls是否存在并有可执行权限
- [ -n "$var" ] :判断$var变量是否有值
- [ "$a" = "$b" ] :判断$a和$b是否相等
示例:
#!/bin/bash if [ ${SHELL} = "/bin/bash" ]; then echo "your login shell is the bash (bourne again shell)" else echo "your login shell is not bash but ${SHELL}" fi
判断登陆shell脚本是否为bash
while循环 if判断 多进程运行 休眠 日期 综合实例
while true do nd=`date "+%H%M"` if [ "0010" == $nd ] || [ "1507" == $nd ];then echo "$nd was found" nohup /usr/local/bin/casperjs /syngooglebudget.js 1 >/cas1.txt 2>&1 & nohup /usr/local/bin/casperjs /syngooglebudget.js 2 >/cas2.txt 2>&1 & sleep 3600s else sleep 5s echo "couln'd foun $nd" fi done