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Questions tagged [unix]

For questions about the Unix operating system.

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18 votes
2 answers
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Why doesn't sed have a j command?

It has always bugged me that sed, which is mostly compatible with ed, doesn't have the same j command (to join two lines together) that ed does. Once upon a time I imagined this was because sed works ...
Steve Summit's user avatar
16 votes
2 answers
3k views

Why would email transmission change the 6-char sequence "0rom "?

According to the Ubuntu uuencode manpage: Specifically, email cannot handle binary data and will often even insert a character when the six character sequence "0rom " is seen. Is (or was) ...
TeaRex's user avatar
  • 967
14 votes
1 answer
3k views

Historically speaking, why is man-db a separate package that is not part of the GNU project?

As far as I understand, GNU had a goal to create a completely free (libre) operating system, and to that end, created FOSS replacements for many UNIX programs. It puzzles me why they didn't try to ...
Kidburla's user avatar
  • 465
4 votes
1 answer
469 views

How can I get X11 to run under SVR4 on 86Box?

Simple and fast question. I want to emulate old Unix Svr4 on 86Box the network and system part is ok I have difficult with X actually this is the sad result after olinit (start OpenLook desktop) or ...
elbarna's user avatar
  • 2,341
17 votes
7 answers
5k views

Why did Linux standardise on RTS/CTS flow control for serial ports

I've recently been working out how best to wire up a serial cable for a vintage plotter, and it's thrown me down the rabbit hole of RS-232. As far as I can tell, many RS-232 devices which act as DTEs (...
Peter Russell's user avatar
31 votes
5 answers
4k views

In what ways was the Windows NT POSIX implementation unsuited to real use?

Windows NT implemented POSIX compatibility because some US government contracts required such. It is said that the POSIX implementation was only pro forma, not intended or suitable for real use (i.e. ...
rwallace's user avatar
  • 63.1k
28 votes
3 answers
8k views

Why was MacOS unix certified?

As I understand it most Linux distros adhere to the UNIX specifications while only a few actually get UNIX certified. If plenty of Linux distros can happily adhere to the standard without being ...
Neil Meyer's user avatar
  • 6,899
5 votes
1 answer
326 views

A SunOS kernel configuration file in the CSRG ISOs?

Does anyone know why there is a SunOS kernel configuration file in the 4.1c.1 BSD directory tree in the CSRG ISOs? How to see that this file exists: McKusick sells the CSRG ISOs. But let's face it, ...
Knickers Brown's user avatar
18 votes
2 answers
3k views

What does 'try again' mean in Unix v6?

I am running a stripped down version of BSD Unix V6, bkunix on my Elektronika BK 0010-01. It has a very limited range of Unix commands. The contents of /bin are: cal cat clock cp date df echo ed halt ...
harlandski's user avatar
  • 2,963
10 votes
1 answer
2k views

Did the rm project remove itself during early development?

Is it true that Brian Kernighan while developing rm accidentally tested the project so that it removed itself? Then, according to story, he had to start over from the beginning because there was no ...
Niklas Rosencrantz's user avatar
19 votes
0 answers
477 views

Is an X Window System older than release 10 available online?

I'm looking for any copy of the X Window System older than release 10. The oldest on x.org is X10R3. Bob Scheifler doesn't have anything. Jim Gettys may have something, but has yet to retrieve it ...
Lars Brinkhoff's user avatar
7 votes
2 answers
411 views

Which historical Unixes supported terminal I/O with five or six bits per character, and with what character sets?

The specification for termios.h includes a facility for controlling the number of bits per character sent over the serial line, the CSIZE and CSn constants. You can request five, six, seven, or eight ...
zwol's user avatar
  • 449
20 votes
3 answers
4k views

when did command line applications start using "-h" as a "standard" way to print "help"?

I am interested to hear about the history because I have a prominent command line product that has decided to use -h for something that does not print a help message. when did command line ...
Trevor Boyd Smith's user avatar
19 votes
10 answers
6k views

Why does cat with no argument read from standard input?

In advice about how to design good CLI commands I read: If your command is expecting to have something piped to it and stdin is an interactive terminal, display help immediately and quit. This means ...
John Skiles Skinner's user avatar
21 votes
2 answers
2k views

Origin of UNIX symbolic links?

When I search the web for information about the origin of UNIX symbolic links, I see "Symbolic links were first introduced into Unix with 4.1c-BSD". But when I go to fact check that, it ...
Knickers Brown's user avatar
25 votes
2 answers
4k views

Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded?

Quoting from Jim Hall's "FreeDOS turns 25 years old: An origin story": Around 1994, Microsoft announced that its next planned version of Windows would do away with MS-DOS. But I liked DOS. ...
ArrayBolt3's user avatar
5 votes
3 answers
550 views

Circuit design tool mentioned in AT&T Unix promotion

In this video from AT&T about Unix is a circuit design tool displayed that is claimed to be based on YACC (timestamped link). Does anyone have information about this tool? Like: Documentation ...
Christian Dreier's user avatar
7 votes
1 answer
664 views

Mainframe Hater's Handbook?

The famous The UNIX-HATERS Handbook claims this mailing list had been inspired by TWENEX-HATERS(1) and other *-LOVERS mailing lists, a long tradition of MIT. Moreover, the quote below implies there ...
Schezuk's user avatar
  • 3,754
7 votes
1 answer
1k views

When did SunOS get a graphical interface?

I understand that the first graphical user interface for SunOS was SunTools (later renamed to SunView), but I cannot find any documentation that states when it was released and for which versions of ...
Brian Reading's user avatar
7 votes
1 answer
303 views

How did Bell Labs start to work on Project MAC?

Did Bell Labs approach MIT or was it the other way around? Did participating in Project MAC come from researchers requesting management at Bell Labs/MIT or did management make the decision due to ...
Knickers Brown's user avatar
50 votes
7 answers
36k views

How could early UNIX OS comprise so few lines of code?

I start my journey to become a hardware / software specialist with an internship in two weeks time and decided to start studying the C language early. I came across this video, Learn C Programming ...
Neil Meyer's user avatar
  • 6,899
21 votes
2 answers
719 views

What is the history of SysV i386 calling convention for struct return?

I would like to understand historical roots of the quirk in the SysV calling convention for the 32-bit x86, which was inherited by the ELF standard, and so remains used on Linux to this day. Consider ...
amonakov's user avatar
  • 313
7 votes
1 answer
633 views

Can you remember the name of a public access Unix system, around 1990/1, Spug or Spud?

Hey I recall accessing a public-access UNIX system in the UK, likely around 1990/91. I seem to recall it gave you shell access but it might actually have only been Mail or UUCP/usenet client? I have a ...
Mike Dent's user avatar
12 votes
6 answers
10k views

What was the original unix font?

I'm looking for a font for a tattoo. I don't have any preferred font so I thought using the original Unix font could be a great reference to the great history. Can't find any reliable information ...
user avatar
7 votes
1 answer
854 views

What is the oldest UNIX available for modern systems?

What is the oldest UNIX(-like) system that can be legally downloaded and run in a VM or emulator on a modern PC running Linux?
Someone's user avatar
  • 173
23 votes
4 answers
4k views

What was the purpose of low-UID special user accounts like “bin”, “sys” or “daemon” in Unix?

In a modern Linux system – modern enough to have upgraded useradd to a version from no earlier than February 2008 – it is usually the case that user accounts with UIDs no less than 1000 (other than ...
user3840170's user avatar
  • 23.2k
4 votes
0 answers
285 views

What does this image in Space Travel represent?

I was touching up the Space Travel article on the Wiki and realized no one had answered a question I posted some time ago. I suspect someone here knows the answer. This image is used in the infobox to ...
Maury Markowitz's user avatar
11 votes
5 answers
3k views

Early implementations of the `system()` call in a consumer OS

Nowadays, it's easy to take for granted the system() call (as defined in POSIX), which allows a user program to easily execute a child process and wait for it to complete. Obviously, this is a trivial ...
Brian H's user avatar
  • 60.9k
5 votes
1 answer
408 views

Why did Dennis Ritchie write that UNIX was a modern implementation of CTSS? [closed]

At the Tenth Hawaii International Conference on the System Sciences in 1977 Dennis Ritchie presented the paper The Unix Time-sharing System: A retrospective in which he states: ...a good case can be ...
Knickers Brown's user avatar
29 votes
2 answers
8k views

Correct pronunciation of `vi` (Unix editor)?

According to this video with Brian Kernighan, the correct pronunciation of the classical Unix editor ed is "Eee. Dee." — not "Edd". So that made me wonder — what about the other ...
Baard Kopperud's user avatar
7 votes
0 answers
239 views

Small format X terminal with EL screen

I remember an ad for a small-format (about as wide as a 60% keyboard) dark-ish grey colored X terminal that had a 12" (?) yellow electroluminescent screen similar to the Grid laptops but higher ...
rbanffy's user avatar
  • 543
10 votes
1 answer
585 views

Nontrivial B program

I have been able to find very little about the B programming language online. the predominant resources seem incomplete, particularly in regards to standard library functions. I have not been able ...
les-citrons's user avatar
30 votes
10 answers
7k views

What happened to all those Unix workstations in the '90s?

Around the early to mid '90s it seems there was a trend for high-end workstations running some form of Unix, and running a RISC or at least some kind of non-x86 architecture. For example: Sun ...
Meatwad's user avatar
  • 373
5 votes
1 answer
780 views

Why did this joke man page use July 16, 1974 as an epoch?

This fake manual page posted to the comp.humor newsgroup jokes that A.out accepts any option passed to it, stalls for a few seconds, and then prints a cryptic message chosen from the list below. The ...
DrSheldon's user avatar
  • 16.4k
9 votes
2 answers
396 views

What environment was Coherent developed with?

Coherent was a Unix clone for IBM compatibles Mark Williams Company produced and sold in the 1980s and early 1990s. What environment and tools was Coherent developed with? Was it cross-developed on ...
Paolo Amoroso's user avatar
4 votes
1 answer
393 views

When did an overlay linker first appear in a PDP-11 UNIX OS?

On a 16-bit system with at most 64K of RAM available for a user program, one would think of having an executable overlay mechanism as an indispensable tool to maximize the amount of memory available ...
Leo B.'s user avatar
  • 19.4k
12 votes
1 answer
831 views

How did early Minix represent processes

Minix, as most know, is a "Unix-like" OS originally used for teaching. Early Minix (v1 and, apparently, v2) ran on the 8088/6 series of processors. It could run on the IBM XT. There have ...
Will Hartung's user avatar
  • 12.3k
18 votes
4 answers
5k views

What is the simplest UNIX system with a MMU?

I was recently looking at a Motorola 68010 and 68451 that have been in some ESD foam on a shelf for a very, very long time. Now, things are all so huge in memory, but BSD4.4-Lite can run in only 256k ...
b degnan's user avatar
  • 1,099
2 votes
2 answers
1k views

How did Unix handle multiprocessing when virtual memory didn't exist?

It seems the first "real" virtual memory management system was the i386 with its powerful paging system that totally isolates processes. How did Unix work before this, ensuring no process ...
user avatar
8 votes
2 answers
2k views

What are the "other crontabs" that /etc/crontab refer to? [closed]

The /etc/crontab file on ubuntu has a header that reads: # /etc/crontab: system-wide crontab # Unlike any other crontab you don't have to run the `crontab' # command to install the new version when ...
GammaGames's user avatar
15 votes
1 answer
2k views

How would old software using the SIGPIPE signal really work if it were to manage _many_ pipes?

I'm wondering what was the thinking behind having a SIGPIPE signal. From my own experience, the first thing I do is turn off that signal (SIGIGN) and use the return value of the calls to make sure it ...
Alexis Wilke's user avatar
37 votes
3 answers
8k views

Why does make only accept tab-indentation?

The syntax for Makefiles requires that indented lines start with a tab, and not a space. So far as I can tell, this has been the case even for very early implementations of make. But even modern-day ...
Omar and Lorraine's user avatar
9 votes
1 answer
1k views

Is it true that "do ... done" blocks in Bash do not end with "od" because od existed before Bash/Bourne shell?

The Wikipedia page about od says: Since it predates the Bourne shell, its existence causes an inconsistency in the do loop syntax. Other loops and logical blocks are opened by the name, and closed by ...
DungSaga's user avatar
  • 561
3 votes
1 answer
551 views

Did DEMOS have a C compiler?

DEMOS was a Soviet operating system derived from BSD Unix. The answer to this question shows that the familiar, English-derived BSD commands were essentially the same in DEMOS. Did DEMOS have a C ...
DrSheldon's user avatar
  • 16.4k
6 votes
2 answers
374 views

DEMOS commands: Cyrillic or Roman letters? Uppercase or lowercase?

DEMOS was a Soviet operating system derived from BSD Unix. Commands in BSD are derived from English words. Did DEMOS use these same commands, develop their own commands but retain the Roman alphabet,...
DrSheldon's user avatar
  • 16.4k
15 votes
3 answers
3k views

What were the differences between Xenix and Unix?

According to https://en.wikipedia.org/wiki/Xenix by the beginning of the nineties, SCO was selling 32-bit 386 versions of both Xenix and Unix. According to https://news.ycombinator.com/item?id=...
rwallace's user avatar
  • 63.1k
39 votes
1 answer
8k views

What was "the shrinkwrap issue?"

I first read "Alice in UNIX Land" (by Lincoln Spector, Texas Computer Currents, Sept. 1989), probably around the time when it was written — and at that time didn't understand very many of ...
StayOnTarget's user avatar
  • 3,886
1 vote
2 answers
618 views

Does an OS, in particular Unix, need special support for terminal colors? [closed]

Also of interest, would be the first OS to support color graphics in other ways (assuming it wasn't a Unix). Background: I'm thinking of playing around with Unix v6 due to all the material available, ...
bbarker's user avatar
  • 279
8 votes
1 answer
994 views

Unix: Why was five (SysV) released *after* seven (V7)?

AT&T released UNIX Version 7 (seven) in 1979. The same company released UNIX System V (five) in 1983. Why did the later release have a lower number?
DrSheldon's user avatar
  • 16.4k
9 votes
3 answers
1k views

Why does -z and -n exist in most shells and /bin/test?

The test command on Unix-like systems provides two special syntax forms for checking whether a string is empty or not: test -z "$foo" # the length of $foo is zero test -n "$foo" # ...
Evan Carroll's user avatar
  • 3,388