[-- Attachment #1: Type: text/plain, Size: 134 bytes --] Hello everyone, What is the special meaning of using / as directory partition in UNIX? And \ as the escape character. Caipenghui [-- Attachment #2: Type: text/html, Size: 142 bytes --]
> What is the special meaning of using / as directory partition in UNIX? And \ as the escape character.
\ came from Multics. The first day Multics ran at Bell Labs Bob Morris
famously typed backslash-newline at the login prompt and crashed the
system.
Multics had a hierarchical file system, too, but I don't recall how
pathnames were punctuated.
Doug
[-- Attachment #1: Type: text/plain, Size: 111 bytes --] > > > Multics had a hierarchical file system, too, but I don't recall how > pathnames were punctuated. > > > [-- Attachment #2: Type: text/html, Size: 512 bytes --]
On Sun, 27 Oct 2019 16:31:28 -0400 Doug McIlroy <doug@cs.dartmouth.edu> wrote: > > What is the special meaning of using / as directory partition in UNIX? And > \ as the escape character. > > \ came from Multics. The first day Multics ran at Bell Labs Bob Morris > famously typed backslash-newline at the login prompt and crashed the > system. > > Multics had a hierarchical file system, too, but I don't recall how > pathnames were punctuated. From what I read: >dir1>dir2>file1 -- absolute: /dir1/di2/file1 file1 -- relative: if >dir1>dir2 is the working dir <file2 -- relative: ../file2 == >dir1>file2 <dir3>file4 -- ../dir3/file3 <<dir4>file5 -- ../../dir4/file5 == >dir4>file5 << is more compact thant ../.. and I like the vertical symmetry of < and >!
[-- Attachment #1: Type: text/plain, Size: 266 bytes --] On Sun, Oct 27, 2019 at 1:43 PM Richard Salz <rich.salz@gmail.com> wrote: > >> Multics had a hierarchical file system, too, but I don't recall how >> pathnames were punctuated. >> > > > > >> /home/CAnthony >user_dir_dir>User>CAnthony ../foo <foo -- Charles [-- Attachment #2: Type: text/html, Size: 1114 bytes --]
> From: Charles Anthony > /home/CAnthony I think it was >user_dir_dir>Group>User, wasn't it? I seem to remember my homedir on MIT-Multics was >udd>CSR>JNChiappa? And I wonder if the 'dd' directory on PDP-7 Unix owe anything to 'udd'? Getting back to the original query, I'm wondering if '/' was picked as it wasn't shifted, unlike '>'? Noel
[-- Attachment #1: Type: text/plain, Size: 1035 bytes --] On Sun, Oct 27, 2019 at 2:31 PM Noel Chiappa <jnc@mercury.lcs.mit.edu> wrote: > > From: Charles Anthony > > > /home/CAnthony > > I think it was >user_dir_dir>Group>User, wasn't it? I seem to remember my > homedir on MIT-Multics was >udd>CSR>JNChiappa? > > >user_dir_dir>Project>User >user_dir_dir Home directories of users >daemon_dir_dir Home directories of daemons >process_dir_dir /proc "Names" are aliases, similar to soft links; "udd" is a name for "user_dir_dir" so ">udd" and ">user_dir_dir" point to the same directory. >user_dir_dir>SysAdmin>admin or >udd>sa>a is ~root/ Circulating back to the original question, backslash is used as an escape character on Multics. "\f" is end-of-file-ish, used eg to leave input mode in text editors. -- Charles And I wonder if the 'dd' directory on PDP-7 Unix owe anything to 'udd'? > > Getting back to the original query, I'm wondering if '/' was picked > as it wasn't shifted, unlike '>'? > > Noel > -- X-Clacks-Overhead: GNU Terry Pratchett [-- Attachment #2: Type: text/html, Size: 2083 bytes --]
[-- Attachment #1: Type: text/plain, Size: 282 bytes --] On 10/27/19 2:49 PM, Charles Anthony wrote: > /home/CAnthony >user_dir_dir>User>CAnthony Is there any relation between Multics' use of ">" as a directory separator and MS-DOS's default use of ">" at the end of the command prompt? -- Grant. . . . unix || die [-- Attachment #2: S/MIME Cryptographic Signature --] [-- Type: application/pkcs7-signature, Size: 4008 bytes --]
[-- Attachment #1: Type: TEXT/PLAIN, Size: 453 bytes --] On Sun, 27 Oct 2019, Grant Taylor via TUHS wrote: > On 10/27/19 2:49 PM, Charles Anthony wrote: >> /home/CAnthony >user_dir_dir>User>CAnthony > Is there any relation between Multics' use of ">" as a directory separator > and MS-DOS's default use of ">" at the end of the command prompt? I can't imagine there's any such connection. MS-DOS got it from CP/M, which didn't even have the concept of subdirectories until after MS-DOS did. -uso.
On 27 Oct 2019 21:11 -0400, from usotsuki@buric.co (Steve Nickolas): > On Sun, 27 Oct 2019, Grant Taylor via TUHS wrote: >> Is there any relation between Multics' use of ">" as a directory >> separator and MS-DOS's default use of ">" at the end of the command >> prompt? > > I can't imagine there's any such connection. MS-DOS got it from CP/M, which > didn't even have the concept of subdirectories until after MS-DOS did. If there was such a relationship, it would probably make more sense for the command prompt termination character to be ":", not ">", as DOS labelled devices as [whatever]: (like "A:" or "NUL:"). So I agree with Steve; I imagine it's unrelated. They just had to use _something_ as a default to indicate that the computer is waiting for a command, and ">" is as good a character as any. In either case, since MS-DOS/PC-DOS did what CP/M already did in that regard, the question would probably need to be posed to Kildall where he got it from. Unless Kildall wrote it down, getting a first hand account on the reasoning behind that particular choice would be... nontrivial. -- Michael Kjörling • https://michael.kjorling.se • michael@kjorling.se “The most dangerous thought that you can have as a creative person is to think you know what you’re doing.” (Bret Victor)
[-- Attachment #1: Type: text/plain, Size: 276 bytes --] On Mon, Oct 28, 2019 at 8:01 AM Michael Kjörling <michael@kjorling.se> wrote: > the question would probably need to be posed to Kildall where he got it > from. > Kildall was in record stating that CP/M's model was RT-11, which came from DOS-11 which came from DOS-8 [-- Attachment #2: Type: text/html, Size: 945 bytes --]
[-- Attachment #1: Type: TEXT/PLAIN, Size: 815 bytes --] On Mon, 28 Oct 2019, Michael Kjörling wrote: > On 27 Oct 2019 21:11 -0400, from usotsuki@buric.co (Steve Nickolas): >> >> I can't imagine there's any such connection. MS-DOS got it from CP/M, which >> didn't even have the concept of subdirectories until after MS-DOS did. > > If there was such a relationship, it would probably make more sense > for the command prompt termination character to be ":", not ">", as > DOS labelled devices as [whatever]: (like "A:" or "NUL:"). So I agree > with Steve; I imagine it's unrelated. They just had to use _something_ > as a default to indicate that the computer is waiting for a command, > and ">" is as good a character as any. 86-DOS actually did use ":" as a prompt character. This was changed for IBM's release, for some clone releases, and for MS-DOS 2.0. -uso.
> From: Charles Anthony >> I think it was >user_dir_dir>Group>User, wasn't it? > user_dir_dir>Project>User Oh, right. Too many years spent on Unix! :-) > "Names" are aliases, similar to soft links I feel like they are more similar to hard links; they belong to a segment, and if the name is given to another segment, and the original segment has only that name, it goes away. (See the discussion under "add_name" in the MPM 'Commands and Active Fuinctions'). Also, Multics does real soft links (too), so names can't be soft links! :-) Noel
Bakul Shah <bakul@bitblocks.com> once said:
> >dir1>dir2>file1 -- absolute: /dir1/di2/file1
> file1 -- relative: if >dir1>dir2 is the working dir
> <file2 -- relative: ../file2 == >dir1>file2
> <dir3>file4 -- ../dir3/file3
> <<dir4>file5 -- ../../dir4/file5 == >dir4>file5
>
> << is more compact thant ../.. and I like the vertical symmetry of < and >!
"Getting Less Than Right" would have been an
interesting title. ;)
Unix uses dot for the current directory. Was
there any notation for this in Multics?
Anthony
[-- Attachment #1: Type: text/plain, Size: 266 bytes --] > > > > Unix uses dot for the current directory. Was > there any notation for this in Multics? > > Not as a special symbol. As a command parameter, [pwd] is equivalent to UNIX `pwd`; [hd] would be equivalent to ~, evaluating to the home directory, -- Charles [-- Attachment #2: Type: text/html, Size: 535 bytes --]
On Mon, 28 Oct 2019, Steve Nickolas wrote:
> 86-DOS actually did use ":" as a prompt character. This was changed for
> IBM's release, for some clone releases, and for MS-DOS 2.0.
The best I've ever seen was RT-11's "." - talk about minimalist...
Actually this thread probably belongs on COFF by now.
-- Dave
On 10/28/19, Dave Horsfall <dave@horsfall.org> wrote:
> On Mon, 28 Oct 2019, Steve Nickolas wrote:
>
>> 86-DOS actually did use ":" as a prompt character. This was changed for
>> IBM's release, for some clone releases, and for MS-DOS 2.0.
>
> The best I've ever seen was RT-11's "." - talk about minimalist...
>
> Actually this thread probably belongs on COFF by now.
RT-11 was following standard DEC practice by using "." as its command
prompt. The "monitor dot" was the command prompt in both TOPS-10 and
TOPS-20.
Most DEC operating systems, including RT-11, TOPS-10/20, and VMS, used
"/" as a prefix on command options; "-" performs this function on UNIX
since "/" is the directory delimiter. Back in the days of stand-alone
programs, physical switches on the console were used to set program
options. This of course won't work when you have multiprogramming. I
was told that DEC chose "/" because it looks like a toggle switch.
Command options in fact were initially called "switches".
-Paul W.