dirname

dirname　　

　　strip last component from file name （strip  除去，剥去） 把文件的绝对路径的最后一个除去  如：　　

dirname /usr/bin/
              -> "/usr"

eric@eric-virtual-machine:~/ethdev1$ dirname /home/eric/  /root/  /opt
/home
/
/

　　eg:　　dirname $0

　　　　返回当前执行脚本的目录　

eric@eric-virtual-machine:~$ cat ethdev1/test.sh 
#!/bin/bash
cd `dirname $0`
echo `pwd`
eric@eric-virtual-machine:~$ ethdev1/test.sh 
/home/eric/ethdev1
eric@eric-virtual-machine:~$ pwd
/home/eric
eric@eric-virtual-machine:~$