pithy sayings for the UNIX sysadmin

One day in late December I was thinking about the issue of sysadmin education. I had just hired a new student, and my previous two had just graduated. So with the new student I'd lose the normal tendency of students to instruct one another to the degree they are able. Of course, teaching the student myself would be time well spent, but rarely is enough time available.

There is, of course, no royal road to learning each site's peculiarities, any more than there is to learning the options to find, but I started to wonder if there was some way to distill bits of general UNIX admin wisdom into small, memorable phrases. Part of my inspiration for this is the many collections of Go proverbs that help beginners remember basic guidelines of good play. Unfortunately, the reasoning behind proverbs like "the monkey jump is worth eight points" isn't necessarily clear to the novice Go player, any more than "cat /dev/null into a large file to free space" is clear to the beginning UNIX admin. So, any collection of memorably pithy aphorisms was going to require some commentary.

After writing up and commenting a few basic aphorisms I already knew needed to be on the list, I sent email to other sysadmins and to two mailing lists with high sysadmin content, asking for more aphorisms. This caused a number of interesting discussions, and even a few new aphorisms. Interestingly, many of the aphorisms have more to do with social issues that technical ones, so "'s' is for sticky; 't' is for /tmp" sits geekily next to the more sober "Does the user think it's fixed?" Most of the aphorisms have turned out to be useful reminders for experienced admins.

A good aphorism should be both memorable and short; alliteration doesn't hurt, either. Many of the aphorisms in the collection are not exactly perfect examples of the genre. I'm a sysadmin, not a poet! But I hope the collective folk wisdom of the ;login: readership can improve them.

Find the aphorisms at <http://www.biostat.wisc.edu/~annis/aphorisms.html>. Here are four from the middle of the list:

• Don't rewrite cat -n
• What have you changed? Whom did you tell?
• What was the return code?
• Where does your symbolic link point today?

Each aphorism comes with commentary. Here's the commentary for the second aphorism above:

• It is vitally important that the sysadmins you work with know what it is you're doing to the system. This goes beyond merely using your version-control system dutifully on any system files. It means telling your co-workers when you do things. This is especially vital when the admin staff is spread throughout a building, city, or the world and direct interaction isn't constant.
• Where I work we have an email alias to which admins are expected to send reports on system things they change that have any small chance of breaking things. This alias sends mail to all the admins, and further is logged into a file — one per year — in a directory devoted to these. Now, this logging may be objected to as being redundant if you're already using version control, but this alias gives the admin a chance to go into background that might be omitted in the change log. It's also a lot easier to grep for changes this way, not surprisingly.

New aphorisms and comments are welcome and encouraged.

[Editor's Note: These really are great! Check them out and share a few of your own. -RK]