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Mar 29, 2024 at 8:48 history edited Stephen Kitt CC BY-SA 4.0
Update TUHS mailing list links.
May 8, 2022 at 5:55 history edited Kusalananda CC BY-SA 4.0
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Mar 18, 2021 at 0:20 history edited JdeBP CC BY-SA 4.0
Have an updated hyperlink.
May 3, 2017 at 22:03 comment added Stéphane Chazelas IIRC, in early Unices, @ was also the kill character (now ^U) and # was erase (now ^H or ^?), so if the early ttys had had the capability to copy-paste, that would have caused interesting behaviours
May 3, 2017 at 21:59 comment added Stéphane Chazelas It looks like sh in PDP-7 Unix and Unix V1 had @/# before it was changed to %/# (v5 had %, but I didn't find what it was for v2, v3, v4).
May 3, 2017 at 20:46 comment added Stéphane Chazelas It would be more correct to say Bourne-like than sh-type. The Thomson shell (sh until Unix v6 before it was replaced by the Bourne shell in v7) had %/# as well. I do not know why the Bourne shell changed it to $. Possibly to make it clear to the user that they were getting a different shell from what they would be used to before. Note that # as a comment leader was introduced by csh. The Bourne shell had no comments until much later (you'd use the : null-command as an ersatz).
May 3, 2017 at 20:42 history edited Kusalananda CC BY-SA 3.0
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May 3, 2017 at 20:06 history edited Kusalananda CC BY-SA 3.0
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May 3, 2017 at 18:57 history edited Kusalananda CC BY-SA 3.0
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May 3, 2017 at 15:45 history edited Kusalananda CC BY-SA 3.0
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May 3, 2017 at 15:37 history edited Kusalananda CC BY-SA 3.0
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May 3, 2017 at 12:31 comment added Stéphane Chazelas @HenningMakholm, yes. It originated even before csh introduced # as a comment leader. Still, it's true that #... lines are comments when copy-pasted even if it was not the intention. I don't know if it was the intention behind ; in rc either, though I observe it's a convenient consequence.
May 3, 2017 at 11:59 comment added hmakholm left over Monica @StéphaneChazelas: Didn't the #-for-root convention originate a long time before terminals where cutting-and-pasting an entire line is easily possible became common?
May 3, 2017 at 9:14 comment added Olivier Dulac a very important choice of # for root is that if you copy a command including it you will not cause damages (as # starts a comment, so will comment your command (well, its first line)). Some people use ">" and if you copy it as well, it can clobber (empty completely) binaries if the command has a full or relative path or if you are in the right directory (and have sufficient rights, for example if you are root). I have seen this happen.
May 3, 2017 at 8:03 vote accept Max Koretskyi
May 3, 2017 at 7:25 comment added Stéphane Chazelas Also note that rc-like shells use ; there (one can copy-paste the full line and that's valid shell code, same idea as root's # prompt being a comment).
May 3, 2017 at 7:23 history edited Kusalananda CC BY-SA 3.0
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May 3, 2017 at 7:22 comment added Stéphane Chazelas Also in zsh (a Bourne-style shell, but with lots of features from tcsh). Note that Bourne-like and csh-like shells typically use # for users of uid 0.
May 3, 2017 at 7:19 history answered Kusalananda CC BY-SA 3.0