Unix Sysadmin

Every Unix user has a bag of those, I figured I'd share mine with you all.

For FreeBSD only: a Perl script to detect IRQ conflicts. Essential!
My finely honed zsh startup scripts. After 5 years of refining them on various Unix systems, I sure hope they are good.
Two useful zsh functions I have been using for years to prepend and append data to shell arrays.
More neat zsh tricks: two quick functions to swiftly convert between decimal and hexadecimal numbering systems, and vice-versa. Of course, Real Programmers can do that without thinking -- these are for the rest of us.
A tool to quickly dump the structure of a MySQL database in ASCII form. Uses mysqlshow.
Strict line formatting : this C program cuts lines at exactly your current terminal width, or 80 chars if undefined.
A Perl one-liner to display files with line numbers.
Another Perl one-liner to convert a Unix timestamp (seconds since 1970) into a human-readable date.
A utility to create an ISO image of a filesystem, for burning onto a CD-ROM. Implemented as a shell script calling mkisofs.
A Unix backup program based on BSD dump, also a shell script.
Sun hacks in C++: to make the keyboard LEDs blink, to turn the monitor on and off, to set the speaker volume, to get monitor data.
Get all information about a symbolic link; the usual stat() call returns data about the object pointed by the link, not the link itself.
Mass-rename files with this zsh script. Eg. to rename all C program files as text files:
```
$ ren -s .c .txt
```
or to rename all the startup scripts:
```
$ ren -p .z dot-z
```
Yet another zsh script I've been carrying around with me for years: it enumerates integers. Very useful in shell scripts of all kind. Eg:
```
% enum 1 3
1
2
3

% enum 0 15 5
0
5
10
15

% enum 99 0 11
99
88
77
66
55
44
33
22
11
0
```