Hack and / - A Little Spring Cleaning
The duck command works great to discover how the space is being used in your home directory, but if you are like me, your home directory is actually on a different partition from the root filesystem. If root is filling up, you still can use the duck command (with a slight tweak) to see which directories consume the most space. You need root privileges to scan all the directories in your root filesystem, so use either su or sudo -s (depending on how you get root permissions) before the duck command:
# cd / # du -ckx | sort -n . . . 243920 ./usr/lib/openoffice 277600 ./var/cache/apt 296376 ./var/cache 475144 ./var 952096 ./usr/share 1099264 ./usr/lib 2259332 ./usr 2908804 . 2908804 total
The extra -x argument I added above tells du to stay on one filesystem—in this case, the root filesystem. Otherwise, if you don't specify -x and you have /home or other directories on different filesystems, du will scan through those partitions as well, so you ultimately will have to skip them out as you scan through your results. As you can see from this output, the /usr directory takes up the bulk of the space on my system, with /usr/lib using almost half the space inside /usr. Also note that /var/cache/apt is listed here—more on how to deal with that below.
Now that you know how your storage is being used, here are a few common-sense ways to manage those files and free some space. If you do Linux programming, build software from source or regularly download tarballs, you probably have these tarballs lying around along with their extracted directories. One easy way to free up space is to delete either the tarball or the extracted directory. If you build your own kernels, you probably have a number of old kernel source trees in /usr/src that you won't ever use again and could stand to delete.
Another common space-waster is old ISO files. Do you really still need that Red Had 7.2 ISO? If so, burn an archive copy or two to CD and then delete the image. Along those same lines, audio files always end up with either an extra copy in a directory for a mix CD, or if you play with video conversion tools like me, you have video files in different phases of being transcoded. If you are done with a project, why not delete them and save the space?
On desktops, but especially on servers, one of the most common places you will find wasted space is in log directories. Logs definitely can be useful, but some logs and some levels of debugging are useful only immediately after a bug is found; the rest of the time they can be truncated or archived safely. Take a look in /var/log/, and see how many large uncompressed log files you have. If the file is no longer being used, you should gzip it. You would be amazed how far you can compress incredibly large log files if you haven't tried it before. If you aren't sure whether a log file is still being written to, use lsof to check:
# lsof | grep "/path/to/filename"
If you regularly find yourself cleaning up or gzipping the rotated log files in /var/log (they append .0, .1 and so on as they are being rotated), then edit /etc/logrotate.conf and enable compression. Usually, this simply requires finding the commented line labeled #compress and uncommenting it.
Another great place to free up space is in your package manager's local package cache. For instance, in the case of Debian-based systems, the packages apt downloads are cached in /var/cache/apt/archives. You could go to that directory and remove the files manually, or you simply could become root and type:
# apt-get autoclean
to remove all the cached packages you no longer need. If you have a distribution that uses yum, the following two commands will clear out the cached headers and packages from your system:
# yum clean headers # yum clean packages
Finally, archiving can be a good solution when cleaning your storage space. If you have a local file server or one machine with more storage than the rest, why not make sure all your large files exist only there and then access them over the network? Alternatively, burn large files you want to keep but don't immediately need to CD or DVD. Once you are done, you'll have plenty of newly freed space—hopefully, enough to last you until next spring.
Kyle Rankin is a Senior Systems Administrator in the San Francisco Bay Area and the author of a number of books, including Knoppix Hacks and Ubuntu Hacks for O'Reilly Media. He is currently the president of the North Bay Linux Users' Group.
Kyle Rankin is a VP of engineering operations at Final, Inc., the author of a number of books including DevOps Troubleshooting and The Official Ubuntu Server Book, and is a columnist for Linux Journal. Follow him @kylerankin.
Fast/Flexible Linux OS Recovery
On Demand Now
In this live one-hour webinar, learn how to enhance your existing backup strategies for complete disaster recovery preparedness using Storix System Backup Administrator (SBAdmin), a highly flexible full-system recovery solution for UNIX and Linux systems.
Join Linux Journal's Shawn Powers and David Huffman, President/CEO, Storix, Inc.
Free to Linux Journal readers.Register Now!
- Devuan Beta Release
- May 2016 Issue of Linux Journal
- EnterpriseDB's EDB Postgres Advanced Server and EDB Postgres Enterprise Manager
- The US Government and Open-Source Software
- The Humble Hacker?
- The Death of RoboVM
- BitTorrent Inc.'s Sync
- Open-Source Project Secretly Funded by CIA
- New Container Image Standard Promises More Portable Apps
- AdaCore's SPARK Pro
In modern computer systems, privacy and security are mandatory. However, connections from the outside over public networks automatically imply risks. One easily available solution to avoid eavesdroppers’ attempts is SSH. But, its wide adoption during the past 21 years has made it a target for attackers, so hardening your system properly is a must.
Additionally, in highly regulated markets, you must comply with specific operational requirements, proving that you conform to standards and even that you have included new mandatory authentication methods, such as two-factor authentication. In this ebook, I discuss SSH and how to configure and manage it to guarantee that your network is safe, your data is secure and that you comply with relevant regulations.Get the Guide