> > I run it but it has error. > > sed 's/^dir-192\.168/dir-10\.0/'` > sed: read error on dir-192.168.0.31: Is a directory > Was there an problem with Frank's response from earlier? rename 192.168 10.0 dir* It is a nice simple solution. You don't have to loop, or use extra commands, just copy and paste that one command to your machine, and all directories will be renamed. I just did it on 1000 directories, and it took 0.052 seconds: [mike at test-box test]$ ls -ld dir-192.168.0.* | wc -l 1000 [mike at test-box test]$ time rename 192.168 10.0 dir* real 0m0.052s user 0m0.012s sys 0m0.040s [mike at test-box test]$ ls -ld dir-10.0.0.* | wc -l 1000 Mike