6 Aug
2018
6 Aug
'18
8:53 p.m.
Hi,
I usually just lurk on this list, but I've been curious lately about the origin of
the symbols at the end of various interactive prompts.
ksh (etc), bash, sh use $ for non-root, and # for root
csh, tcsh and zsh use % for non-root and # for root
fish and things like mysql, ftp, and interactive shells for a lot of scripting languages
use >
rc uses ;
Where do these different conventions originate?
B
6 Aug
6 Aug
9:16 p.m.
The early shells (Thompson, Mashey) used "% " for regular user (and # for
root). The Thompson shell didn't have a setable prompt.
The Bourne shell (V7) had setable PS1 (start of command) and PS2 (continuation prompts)
and set the to "$ " and "> " respectively. Again # was used for
root.
-----Original Message-----
From: TUHS <tuhs-bounces(a)minnie.tuhs.org> On Behalf Of Brian Zick
Sent: Monday, August 6, 2018 4:54 PM
To: tuhs(a)minnie.tuhs.org
Subject: [TUHS] Origins of shell prompt suffixes % $ > #
Hi,
I usually just lurk on this list, but I've been curious lately about the origin of
the symbols at the end of various interactive prompts.
ksh (etc), bash, sh use $ for non-root, and # for root
csh, tcsh and zsh use % for non-root and # for root
fish and things like mysql, ftp, and interactive shells for a lot of scripting languages
use >
rc uses ;
Where do these different conventions originate?
B
9:33 p.m.
On 6 August 2018 at 17:16, <ron(a)ronnatalie.com> wrote:
The early shells (Thompson, Mashey) used "%
" for regular user (and # for
root). The Thompson shell didn't have a setable prompt.
The Bourne shell (V7) had setable PS1 (start of command) and PS2
(continuation prompts) and set the to "$ " and "> " respectively.
Again
# was used for root
Okay, but why did Bourne switch from "%" to "$"? Was it to inform the
user
that they were using the new shell as opposed to the old one, or was there
some other reasoning behind the switch?
-Henry
7 Aug
7 Aug
1:10 a.m.
Off topic to one side:
I was told, but cannot recall by whom, that the csh decision to use %
when the bourne shell had $ was to make it clear which syntax was
expected by the user. tcsh inherited from csh. Bash/Zsh/Ash/Ksh
inherited from sh.
Obviously that is outside the strict terms of the question and lies in
hands, not this lists main focus.
-G
On Tue, Aug 7, 2018 at 7:33 AM, Henry Bent <henry.r.bent(a)gmail.com> wrote:
On 6 August 2018 at 17:16, <ron(a)ronnatalie.com>
wrote:
The early shells (Thompson, Mashey) used "% " for regular user (and # for
root). The Thompson shell didn't have a setable prompt.
The Bourne shell (V7) had setable PS1 (start of command) and PS2
(continuation prompts) and set the to "$ " and "> " respectively.
Again #
was used for root
Okay, but why did Bourne switch from "%" to "$"? Was it to inform
the user
that they were using the new shell as opposed to the old one, or was there
some other reasoning behind the switch?
-Henry
1:12 a.m.
I was told, but cannot recall by whom, that the csh
decision to use % when the bourne shell had $ was to make it clear which syntax was
expected by the user. tcsh inherited from csh. Bash/Zsh/Ash/Ksh inherited from sh.
I don't buy it. CSH predates the Bourne shell by a year. I suspect it used %
because the V6 shell it replaced used %.
1:10 a.m.
I suspect it was Steve’s personal preference on the Bourne shell. There’s next to no
comments in the thing and the document on the shell just mentions the defaults and that
you can change it.
Just for completeness, the PWBSH appears to allow the prompt to be changed with a command
line argument.
We used to have a shell called “uu” at Hopkins which was sort of a prehistoric “sudo” that
ran certain commands (icheck/dcheck/etc…) as root while setting back to the regular uid
for others. It used “@ “ for a prompt.
From: TUHS <tuhs-bounces(a)minnie.tuhs.org> On Behalf Of Henry Bent
Sent: Monday, August 6, 2018 5:33 PM
To: TUHS main list <tuhs(a)minnie.tuhs.org>
Subject: Re: [TUHS] Origins of shell prompt suffixes % $ > #
On 6 August 2018 at 17:16, <ron(a)ronnatalie.com <mailto:ron@ronnatalie.com> >
wrote:
The early shells (Thompson, Mashey) used "% " for regular user (and # for
root). The Thompson shell didn't have a setable prompt.
The Bourne shell (V7) had setable PS1 (start of command) and PS2 (continuation prompts)
and set the to "$ " and "> " respectively. Again # was used for
root
Okay, but why did Bourne switch from "%" to "$"? Was it to inform the
user that they were using the new shell as opposed to the old one, or was there some other
reasoning behind the switch?
-Henry
6:54 a.m.
On 6 Aug 2018 21:53 +0100, from brian(a)zick.io (Brian Zick):
rc uses ;
Not sure what came first, and not up to digging out the history books,
but these days, a plain `;` for a prompt has a distinct advantage in
that you can copy the whole line and paste it into another shell, and
the shell will do The Right Thing (tm) as long as (as is, I believe,
done by all of the major shells at least) it uses `;` for command
separation.
--
Michael Kjörling • https://michael.kjorling.se • michael(a)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)
8:02 a.m.
On 7 Aug 2018 06:54 +0000, from michael(a)kjorling.se (Michael Kjörling):
the shell will do The Right Thing (tm)
I suspect I must stand corrected on this. Turns out that at least GNU
bash 4.4.12(1) seems to not like a `;` at the beginning of the command
line.
$ /bin/bash --version | head -n1
GNU bash, version 4.4.12(1)-release (x86_64-pc-linux-gnu)
$ /bin/bash
$ ; true
bash: syntax error near unexpected token `;'
$ echo $?
2
$
Hopefully other shells are more sane.
--
Michael Kjörling • https://michael.kjorling.se • michael(a)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)
8:23 a.m.
On Tue, 7 Aug 2018, Michael Kjörling wrote:
Hopefully other shells are more sane.
The MacBook here runs GNU bash, version 3.2.57(1)-release
(x86_64-apple-darwin16) and is equally busted, as is plain "sh" on both
the Mac and FreeBSD (I can't be bothered checking the Penguin); I use ZSH
on FreeBSD and it does The Right Thing (tm), as does ZSH on the Mac.
-- Dave
8:37 a.m.
On Tue, Aug 07, 2018 at 06:23:37PM +1000, Dave Horsfall wrote:
On Tue, 7 Aug 2018, Michael Kjörling wrote:
I have tried all the shells I have on my linux box. It turns out that
only ksh and zsh like a ";" at the beginning of the line. Otherwise,
bash, busybox, ash/dash, mksk, posh, and yash can't bear it.
I really don't see the point of using ";", especially if you need to
make it clear if a command needs to be run by root.
$ ;-P
sh: 1: Syntax error: ";" unexpected
--
[ ~.,_ Enzo Nicosia aka KatolaZ - Devuan -- Freaknet Medialab ]
[ "+. katolaz [at] freaknet.org --- katolaz [at] yahoo.it ]
[ @) http://kalos.mine.nu --- Devuan GNU + Linux User ]
[ @@) http://maths.qmul.ac.uk/~vnicosia -- GPG: 0B5F062F ]
[ (@@@) Twitter: @KatolaZ - skype: katolaz -- github: KatolaZ ]
Hopefully other shells are more sane.
The MacBook here runs GNU bash, version 3.2.57(1)-release
(x86_64-apple-darwin16) and is equally busted, as is plain "sh" on both the
Mac and FreeBSD (I can't be bothered checking the Penguin); I use ZSH on
FreeBSD and it does The Right Thing (tm), as does ZSH on the Mac.
-- Dave 
10:45 a.m.
Michael Kjörling <michael(a)kjorling.se> wrote:
I suspect I must stand corrected on this. Turns out that at least GNU
bash 4.4.12(1) seems to not like a `;` at the beginning of the command
line.
This is a consequence of the POSIX shell grammar, which doesn't allow
empty commands.
http://pubs.opengroup.org/onlinepubs/9699919799.2013edition/utilities/V3_ch…
The prompt I have used since about 1997 (and I can't remember where I got
it from - somewhere on Usenet, probably) in its most distilled form is
:;
although in practice I have a load of extra fluff for username, hostname,
CWD, etc. usw.
Tony.
--
f.anthony.n.finch <dot(a)dotat.at> http://dotat.at/
Fair Isle, Faeroes: South or southwest 4 or 5, occasionally 6 for a time.
Slight or moderate, occasionally rough for a time. Showers. Moderate or good.
5:35 p.m.
The prompt I have used since about 1997 (and I
can't remember where I got
it from - somewhere on Usenet, probably) in its most distilled form is
:;
I forget where I stole this from. It lives in $home/lib/profile on my
Plan9 machines:
# /n/sources/contrib/lyndon/prompt.rc
fn : {}
fn setprompt {
prompt = (': '^`{cat /dev/user}^@^`{cat
/dev/sysname}^':'^`{pwd}^'; ' ' ')
}
fn cd { builtin cd $* && setprompt }
setprompt
8 Aug
8 Aug
2:38 p.m.
On 07/08/2018, Tony Finch <dot(a)dotat.at> wrote:
Michael Kjörling <michael(a)kjorling.se> wrote:
Good point (and [t]csh on Solaris does not care).
I suspect I must stand corrected on this. Turns out that at least GNU
bash 4.4.12(1) seems to not like a `;` at the beginning of the command
line.
This is a consequence of the POSIX shell grammar, which doesn't allow
empty commands.
http://pubs.opengroup.org/onlinepubs/9699919799.2013edition/utilities/V3_ch…
prompt I have used since about 1997 (and I can't
remember where I got
it from - somewhere on Usenet, probably) in its most distilled form is
:;
I will, no doubt, be flayed on this list but I tend to use "=> ".
N.
although in practice I have a load of extra fluff for username, hostname,
CWD, etc. usw.
Tony.
--
f.anthony.n.finch <dot(a)dotat.at> http://dotat.at/
Fair Isle, Faeroes: South or southwest 4 or 5, occasionally 6 for a time.
Slight or moderate, occasionally rough for a time. Showers. Moderate or
good.
7 Aug
7 Aug
11:24 a.m.
On 07/08/2018 09:02, Michael Kjörling wrote:
On 7 Aug 2018 06:54 +0000, from michael(a)kjorling.se
(Michael Kjörling):
ksh and sh on an IRIX system don't like it either:
$ ;
ksh: syntax error: `;' unexpected
$
csh and tcsh don't mind.
Of course it works in rc itself, which is the point, really, and I
wonder how often anyone pasted from one shell into another. All the rc
use I've seen did indeed use "; " as the prompt, but that was all at the
University of York, starting in 1993.
--
Pete
Pete Turnbull
the shell will do The Right Thing (tm)
I suspect I must stand corrected on this. Turns out that at least GNU
bash 4.4.12(1) seems to not like a `;` at the beginning of the command
line.
$ /bin/bash --version | head -n1
GNU bash, version 4.4.12(1)-release (x86_64-pc-linux-gnu)
$ /bin/bash
$ ; true
bash: syntax error near unexpected token `;'
$ echo $?
2
$
Hopefully other shells are more sane. 
8 Aug
8 Aug
7:55 p.m.
On Tue, Aug 07, 2018 at 08:02:56AM +0000, Michael Kjörling wrote:
I suspect I must stand corrected on this. Turns out
that at least GNU
bash 4.4.12(1) seems to not like a `;` at the beginning of the command
line.
I can't recall where I got this from, but I tend to use the following
on bourne style shells; bash (and others) seem happy with it for copy/paste:
h=copper$; tty
/dev/pts/0
h=copper$; h=copper$; tty
/dev/pts/0
h=copper#; tty
/dev/pts/0
h=copper#; h=copper#; tty
/dev/pts/0
'copper' being the hostname, $/# as per usual.
DF
7 Aug
7 Aug
7:31 a.m.
On Mon, Aug 06, 2018 at 09:53:33PM +0100, Brian Zick wrote:
rc uses ;
Does it? 10th edition Unix and Plan 9 rc both have ('% ' ' ') as the
default value of $prompt. At least that's how it's described in the
manual. None of the v8/9/10 tarballs in the archive contain rc code,
but some contain manual source, and those describe % prompts.
I've seen other references to ; (presumably ('; ' ' ')) as the
rc
prompt but I've never seen it in the wild. Does anyone here know what
the story is?
khm
7:50 a.m.
Kurt H Maier <khm(a)sciops.net> wrote:
On Mon, Aug 06, 2018 at 09:53:33PM +0100, Brian Zick
wrote:
I believe that Tom Duff's rc does indeed use ('% ' ' '). But I
think that
Byron Rakitsis's version changed the default to ('; ' ' ')
exactly for
the reason that it's copyable/pastable.
HTH,
Arnold
rc uses ;
Does it? 10th edition Unix and Plan 9 rc both have ('% ' ' ') as the
default value of $prompt. At least that's how it's described in the
manual. None of the v8/9/10 tarballs in the archive contain rc code,
but some contain manual source, and those describe % prompts.
I've seen other references to ; (presumably ('; ' ' ')) as the
rc
prompt but I've never seen it in the wild. Does anyone here know what
the story is?
khm 
7:57 a.m.
On Tue, 07 Aug 2018 00:31:36 -0700 Kurt H Maier <khm(a)sciops.net> wrote:
On Mon, Aug 06, 2018 at 09:53:33PM +0100, Brian Zick
wrote:
The es shell (by Haar and Rakitzis) used ; - the reason (as
per the man page)is that a user can cut-n-paste a previous
line to rexecute it (for the same reason people use term% and
cpu% functions to execute their args). Es syntax was derived
from rc, which may be why the confusion.
rc uses ;
Does it? 10th edition Unix and Plan 9 rc both have ('% ' ' ') as the
default value of $prompt. At least that's how it's described in the
manual. None of the v8/9/10 tarballs in the archive contain rc code,
but some contain manual source, and those describe % prompts.
I've seen other references to ; (presumably ('; ' ' ')) as the
rc
prompt but I've never seen it in the wild. Does anyone here know what
the story is?
3:15 p.m.
rc uses ;
Does it? 10th edition Unix and Plan 9 rc both have ('% ' ' ') as the
default value of $prompt. At least that's how it's described in the
manual. 
3:52 p.m.
On vacation, with just an iPad keyboard, so I apologize for not doing more
digging. As I noted, when taking the blame for the Great Echo Schism, my
early exposure to a hp2640 terminal that allowed “rentry” of a previous
command was partly to blame. It also led me to use a PS1 ending in @, the
default line-kill. When I reentered a command, the @ wiped out the prompt
stuff, and only the command survived.
On Tue, Aug 7, 2018 at 10:15 AM Brian Zick <brian(a)zick.io> wrote:
In NetBSD 7 the default is ';', but I don't see any reference to a
default
$prompt in the manual on that system. I wonder if this was a change unique
to Berkeley.
B
rc uses ;
Does it? 10th edition Unix and Plan 9 rc both have ('% ' ' ') as
the
default value of $prompt. At least that's how it's described in the
manual. 
6:51 p.m.
C??g <ca6c(a)bitmessage.ch> wrote:
Brian Zick wrote:
Brian was referring to rc(1) in NetBSD. I suspect it's Byron's rc
and I think the default there is ';'.
Arnold
In NetBSD 7 the default is ';', but I
don't see any reference to a
default $prompt in the manual on that system.
It's not. '$' is default for sh and ksh, and '%' for csh. I
think
it maybe has never been ';'.
--
ca??c
7:06 p.m.
On Tue, Aug 7, 2018, at 8:00 PM, Cág wrote:
arnold wrote:
Yes, I was referring to the rc in pkgsrc.
B
Brian was referring to rc(1) in NetBSD. I
suspect it's Byron's rc
and I think the default there is ';'.
rc is not shipped with NetBSD. There's Byron's rc in pkgsrc, so it could
be that.
2086
days inactive
2088
days old
24 comments
18 participants
participants (18)
-
arnold＠skeeve.com -
Bakul Shah -
Brian Zick -
Clem Cole -
Cág -
Dave Horsfall -
Derek Fawcus -
George Michaelson -
Henry Bent -
John P. Linderman -
KatolaZ -
Kurt H Maier -
Lyndon Nerenberg -
Michael Kjörling -
Nemo -
Pete Turnbull -
ron＠ronnatalie.com -
Tony Finch