I am new to Shell Scripts and not aware of the syntax.
我有我推到我的Android设备,然后用“busybox的DOS2UNIX的”转换成为一个shell脚本:在shell脚本中检查字符串错误是否为空?
adb shell busybox dos2unix /data/local/myShellScript.sh
在剧本我想检查一个字符串是否为空或不 ? 但我得到错误:'意外的操作符/操作数'。
下面是我的代码:
echo "Getting a PID (Process ID) from a file" ;
pid=`cat /sdcard/PIDofTask.txt` ;
echo "PID of task is : " $pid ;
echo "Checking if the pid exists, to verify the process is running" ;
pidString=$(ps | grep ${pid}) ;
echo "PID string : " $pidString ;
if [ $pidString ] ;
then
echo "pid String is not empty" ;
else
echo "pid String is empty" ;
fi ;
输出:
Getting a PID (Process ID) from a file
PID of task is : 11571
Checking if the pid exists, to verify the process is running
PID string : root 11571 8082 4180 1828 poll_sched 7faa42dcdc S sh
/data/local/myShellScript.sh[2]: [: 11571: unexpected operator/operand
pid String is empty
我也曾尝试[-n $ pidString]也[-z $ pidString]选项。但是两者都给出了错误。
我在哪里做错了? 真的很感谢帮助...
也是我认为声明 “pidString = $(PS | grep的$ {} PID)” 是不正确。你是否试图检查pid是否激活? –