The Joys of xargs

You can use xargs if you need to rename lots of files (e.g. datestamping). This command will rename each file in the current directory from filename.txt to 20080815-filename.txt:

ls | xargs -I {} mv {} 20080815-{}

This works because {} is a placeholder meaning "the current argument". (You can use xxx or yyy or any other string instead of {} if you want, as well, and it'll do exactly the same thing.) -I implies -n1, because you want to act on each file individually.

Or you might want to move all the files in directory 1 into directory 2:

ls dir1 | xargs -I {} -t mv dir1/{} dir1/{}

Conclusion

I've concentrated here on using xargs to manipulate files in various ways, but you can use the same tricks for other commands. For example, if you have a file containing a list of IP addresses,

cat iplist | xargs -n1 nmap -sV

would run nmap on each IP address at a time. Play around with it a bit and see what you can do!

This article was first published on LinuxPlanet.com.