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Comment by WestCoastJustin | Hacker News Reader

If anyone is interested there were several great posts on Hacker News a while about about useful UNIX commands [1, 2, 3]. I have also created several screencasts about command commands like the following [4], and one about the Filesystem Hierarchy Standard [5].

  ls man pwd cd top ps df du cp mv rm mkdir rmdir less cat vi

[1] https://news.ycombinator.com/item?id=6046682

[2] https://news.ycombinator.com/item?id=5022457

[3] https://news.ycombinator.com/item?id=4985393

[4] http://sysadmincasts.com/episodes/13-crash-course-on-common-...

[5] http://sysadmincasts.com/episodes/12-crash-course-on-the-fil...

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Great links, though I admit when I saw the OP I was expecting content like that and was pleasantly surprised that they really were "Unix commands I wish I'd discovered years earlier", and not the standard array of unix tips+tricks that you can get by without for awhile but as you become more advanced become second-nature.

"Man ascii." The number of times that I wound up generating my own ascii table from whatever language I was working with...

"xxd" I always either used search in emacs hex-mode (which I find cumbersome and annoying but haven't taken the time to customize), or rolled my own search using a programming language. This would have come in handy SO many times back when I used to muck around with videogame save files and the like. I never even knew it existed nor how to discover that it did.

'cal' I learned about early on so never missed it and the 'ssh' stuff kind of fits into the regular "unix tips and tricks" category.

re: ascii tables

You reminded me of something. There is actually a really cool and simple site called asciiflow [1], which I use all the time to draw diagrams for explaining things in email, etc. It's pretty cool, and was even submitted several times to HN [2, 3].

[1] http://www.asciiflow.com/#Draw

[2] https://news.ycombinator.com/item?id=2847177

[3] https://news.ycombinator.com/item?id=3598177

Wow. This is really cool! Not only can you make the ascii drawings, but there is an integration with a service called ditaa (unaffiliated) that then turns your ascii drawings into actual images. I am keeping these. http://ditaa.sourceforge.net/

I can't browse www.asciiflow.com, the name does not resolve:

  $ host www.asciiflow.com
  Host www.asciiflow.com not found: 3(NXDOMAIN)

Caused by both authoritative nameservers for asciiflow.com which return the correct answer (a CNAME to ghs.google.com), but with status=NXDOMAIN (wtf?):

  $ dig +short asciiflow.com ns
  ns2.123-reg.co.uk.
  ns.123-reg.co.uk.
  $    ; <<>> DiG 9.8.1-P1 <<>> @ns2.123-reg.co.uk www.asciiflow.com
  ; (1 server found)
  ;; global options: +cmd
  ;; Got answer:
  ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 65092
  ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 0
  ;; WARNING: recursion requested but not available
  
  ;; QUESTION SECTION:
  ;www.asciiflow.com.           IN      A
  
  ;; ANSWER SECTION:
  www.asciiflow.com.    86400   IN      CNAME   ghs.google.com.
  
  ;; AUTHORITY SECTION:
  google.com.           14400   IN      SOA     ns.123-reg.co.uk. hostmaster.google.com. 2013052701 86400 0 604800 86400
  
  ;; Query time: 207 msec
  ;; SERVER: 92.51.159.40#53(92.51.159.40)
  ;; WHEN: Wed Sep 11 00:27:52 2013
  ;; MSG SIZE  rcvd: 123

Its really cool that this is a GWT app as well - don't see much of those these days.

xxd, together with xxd -r, is a rather practical way to turn vim into a hex editor.

You should do a screencast of such infinitely useful classics as tac, tsort, and sl.

(Actually, I have found use for those first two on occasion. ;)

Thanks for the suggestion! Actually, I initially wanted to do one on more advanced commands, but I thought I'd better lay a foundation first. I also want to cover using pipe (|) to chain these commands together. I'll make sure to include these.

Don't miss xargs.

tsort is one of my favorites, mostly because it's totally pointless until you need it and then it works exactly right. I love it.

Wow. I just read the man page for tsort and I am none the wiser.

  tsort takes a list of pairs of node names representing directed arcs in a 
  graph and prints the nodes in topologi-cal order on standard output.

It's not often I understand nothing on a man page. But this time, I'm stumped!

Say you have a set of tasks you need to do, and some of those depend on others. Now, you want to perform those tasks in order. The question then becomes: in which order? That's the problem that tsort (1) solves.

It's a way to do some of what make does without having to write a Makefile. 99.9% of the time, it never comes up, but when it does, it is very, very handy to be able to this in a shell pipeline. HTH.

http://en.wikipedia.org/wiki/Topological_sorting

Me too. Then I read the info, it gives an interesting historical perspective of why tsort came about. On a system with GNU utils installed:

  info coreutils 'tsort invocation'

i usually click those links, see the stuff and roll up my eyes. nothing learned, but upvote so more people learn about them anyway.

this time, the very first one `man ascii` got me. Genius. Never though about looking for that in man before. But in my defense, this was added in 1999 :)

> An ascii manual page appeared in Version 7 of AT&T UNIX.

I'm sure that was a bit earlier than 1999.

true. it appeared in 1985

http://man.cat-v.org/unix_8th/7/

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