PATH路径简单理解

[root@localhost kang]# vi yy
echo YY
[root@localhost kang]# chmod +x yy
[root@localhost kang]# ./yy
YY
[root@localhost kang]# pwd
/root/kang

目的修改PATH路径，让用户在任何目录下输入yy都可执行
[root@localhost kang]# PATH="$PATH:/root/kang"      #临时生效
[root@localhost kang]# echo $PATH
/usr/local/java//bin:/usr/local/java//bin:/usr/lib64/qt-3.3/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin:/root/kang

验证：
[root@localhost /]# pwd
/
[root@localhost /]# yy
YY

永久生效方法：
[root@localhost ~]# vi /etc/profile             #永久生效
[root@localhost ~]# source /etc/profile     #立即生效
[root@localhost ~]# yy
YY