Tinkering is all fun and games, until it’s 4 am, your vision is blurry, and thinking straight becomes a non-option, or perhaps you just get overly confident, type something and press enter before considering the consequences of the command you’re about to execute… And then all you have is a kernel panic and one thought bouncing in your head: “damn, what did I expect to happen?”.
Off the top of my head I remember 2 of those. Both happened a while ago, so I don’t remember all the details, unfortunately.
For the warmup, removing PAM. I was trying to convert my artix install to a regular arch without reinstalling everything. Should be kinda simple: change repos, install systemd, uninstall dinit and it’s units, profit. Yet after doing just that I was left with some PAM errors… So, I Rdd-ed libpam instead of just using --overwrite. Needless to say, I had to search for live usb yet again.
And the one at least I find quite funny. After about a year of using arch I was considering myself a confident enough user, and it so happened that I wanted to install smth that was packaged for debian. A reasonable person would, perhaps, write a pkgbuild that would unpack the .deb and install it’s contents properly along with all the necessary dependencies. But not me, I installed dpkg. The package refused to either work or install complaining that the version of glibc was incorrect… So, I installed glibc from Debian’s repos. After a few seconds my poor PC probably spent staring in disbelief at the sheer stupidity of the meatbag behind the keyboard, I was met with a reboot, a kernel panic, and a need to find another PC to flash an archiso to a flash drive ('cause ofc I didn’t have one at the time).
Anyways, what are your stories?
First, the classical typo in a bash script:
which is why I like to add a set -u at the begining of a script.
The second one is not with a Linux box but a mainframe running AIX:
If on Linux killall java kills all java processes, on AIX it just ignore the arguments and kill all processes that the user can kill. Adios the CICS region 😬 (on the test env. thankfully)
jfc, is ignoring arguments the intended behavior?
On a real UNIX (not only AiX) killall is part of the shutdown process - it gets called by init at that stage when you want to kill everything left before reboot/shutdown.
Linux is pretty unique in using that for something else.
I didn’t know that, good to know.
They could have send a SIGTERM by default instead of a SIGKILL. I would not have corrupt everything 😅
killall typically sends SIGTERM by default. It accepts a single argument, the signal to send - so shutdown would call it once with SIGTERM, then with SIGKILL. killall is not meant to to be called interactively - which worked fine, until people who had their first contact with UNIX like systems on Linux started getting access to traditional UNIX systems.
It used to be common to discourage new Linux users from using killall interactively for exactly that reason. Just checked, there’s even a warning about that in the killall manpage on Linux.
Yes: same command name, two different semantics:
AIX man page
The Linux one
Cross-Unix scripting is fun ☺️
Wow, the last one is quite unexpected. What a useful command
after reading what “set -u” does, bro this should be default behavior, wtf?