alt Hacker NewsIn the mid-90s I taught a night class on Unix, and was experimenting with shell scripts from The Unix Programming Environment. There was an example using a loop and the who command to alert you when someone logged onto your local system. My cousin was a professor at a university several states away, and we had already figured out the talk command. So I decided to expand the examples in the book to use finger. By parsing the reply, somehow I could tell if my cousin was logged on, and I would send myself a notice. There was an ISP in the same building, and one day the ISP engineer came to visit me with a stern look. He asked, "By any chance are you sending a finger command every two minutes to this university's mainframe?" I proudly answered, "As a matter of fact, yes, I am!". I eagerly got out my Unix book to show him what I was doing. He just said, "Stop doing that. They have a system console logging program that has churned out dozens of pages of paper printouts because of you". I sheepishly acknowledged my mistake and quit running the script.
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I was sure this story was going to end with your script causing chaos by calling finger in a busy loop. But every 2 minutes! Even in the 90s, that's a pretty mild amount of network traffic.
If running finger causes a paper printout, the issue appears to be with the latter.
Speaking of finger, console logging, and the 90s: when I was a freshman in college I took a Pascal programming course. We were assigned accounts on a cluster of AT&T 3B2 systems running SVR3. The students only had access to a terminal lab; the servers were upstairs, out of our reach.
There was no disc quota or significant restriction on the resources available to us, so I became a video game mogul. I found all the freeware download sites, and I became an expert on portability, tweaking and compiling game software to run on our idiosyncratic system.
As students, we made extensive use of "finger", "w", "who", and "write". We also knew the existence of "wall" and the like. So it was de rigeur for us all to write a little something into our .project and our .plan files. I took it much further, and discovering VT100 escape sequences, produced an animated .plan file which erased and mutated some of the immutable datapoints displayed, such as replacing my $HOME directory with "/" and some script-kiddie flexes like "I have root access... you know!"
Subsequently I explored the system extensively and eventually found /etc/passwd, and for reasons, attempted to "su" to every single account I found in there, most of them being system maintenance accounts. Due to logging and auditing, of course, these blatant, brazen failures captured the attention of the unseen administrator.
I received an email that made my blood run cold. The admin (and I still remember his name 37 years later) told me everything I had done in detail, and said that claiming "root access" was equivalent to telling airport officials that I was carrying a bomb. And there were no academic sanctions or threats in this email, but his veritable omniscience and dead-serious tone made me reconsider many of my life choices at the age of 19. Today, I am thankful for this guy putting things into perspective, that Unix was not just a huge game of Zork or Nethack, and he definitely inspired my career goal as systems admin.
> finger [...] dozens of pages of paper printouts
I know just the poetry to go with that story:
--Omar Khayyám, 11th-century, translation