The history of Unix systems and their main components. Please DO NOT USE this tag for shell-related questions; use [tag:command-history] instead.

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10
votes
3answers
732 views

Why does the “she-bang” begin with a “#!”?

Why does the "she-bang" begin with a #!, like #!/bin/bash? I have always accepted that this how it is done, but is there a reason behind it? Why start with #; isn't that usually a comment? Or is it ...
2
votes
1answer
46 views

Why is vdir still around?

After installing Debian 8, I started poking around /bin (as I'm always wont to do), and I noticed that ls and vdir share, not only the same manpage (except for the whatis line), but the exact same ...
22
votes
1answer
1k views

What does Ritchie's 1979 PDP-11 `/usr/games/bcd` do?

I recently tried the simh emulator pdp11. The disk image I used can be found on the internet, and instructions for booting it are here. Presumably it belonged to Dennis Ritchie, as the username is ...
24
votes
3answers
12k views

Why does Unix time start at 1970-01-01

Why does Unix time start at 1970-01-01? Why not 1971-01-01 or any other date?
6
votes
2answers
165 views

What's the story behind command file's suggestion?

While I'm reading file(1) I noticed this in the man page (emphasis mine): When adding local definitions to /etc/magic, make sure to preserve these keywords. Users depend on knowing that all the ...
0
votes
2answers
110 views

When was the threading implemented in unix?

Which is the first Unix version or Linux version which implemented threads. And in which version bound and unbound threads were implemented? I know that in current Linux version threads are unbound by ...
31
votes
4answers
4k views

Why are UNIX/POSIX system call namings so illegible?

What is the reason to use such untelling system call names like time and creat instead of getCurrentTimeSecs and createFile or, maybe more suitable on Unix get_current_time_secs and create_file. Which ...
5
votes
3answers
334 views

Why BitchX is called BitchX?

Well, the title is pretty much self-explanatory, but for sake of completeness, I'm curious to know the reason for the name of BitchX. I searched on internet for etymology but it was a fail. I hope ...
33
votes
4answers
8k views

What did Ken Thompson mean when he said, “I'd spell creat with an 'e'.”

Ken Thompson, the creator of Unix, was once asked what he'd do if he had it to do over again. He said, "I'd spell creat with an 'e'." What is Ken referring to? Is there a "creat" command?
23
votes
2answers
1k views

Patching a binary with dd

I have read this quote (below) several times, most recently here, and am continually puzzled at how dd can be used to patch anything let alone a compiler: The Unix system I used at school, 30 ...
1
vote
0answers
50 views

how to copy files using TTY teminal from one pc to another connected through same home network

In my academic lab my friend copied files from one computer to another that were serially connected using the tty4. How could he have done this if there was no internet and he didn't install any new ...
1
vote
0answers
30 views

Is Cat-v.org an official subsidiary website of Plan 9 from Bell Labs?

I was wondering, since it seems to be one of the only websites where I can seemingly legally download historic Unix documents.
90
votes
3answers
17k views

Why are tar archive formats switching to xz compression to replace bzip2 and what about gzip?

More and more tar archives use the xz format based on LZMA2 for compression instead of the traditional bzip2(bz2) compression. In fact kernel.org made a late "Good-bye bzip2" announcement, 27th Dec. ...
3
votes
2answers
2k views

What does chmod stand for?

In order to memorize a command, it is usually a good idea to learn where it's name comes from. For example, cp comes from copy. usermod means "User Modifiy" (at least I guess so). Where does chmod ...
2
votes
1answer
37 views

Why should you avoid “stringently columnar” input formats?

Doug McIlroy, the inventor of Unix pipes and one of the founders of the Unix tradition, had this to say at the time [McIlroy78]: (ii) Expect the output of every program to become the input to ...
18
votes
3answers
594 views

Use of ^ as a shell metacharacter

I wrote a small script today which contained grep -q ^local0 /etc/syslog.conf During review, a coworker suggested that ^local0 be quoted because ^ means "pipe" in the Bourne shell. Surprised by ...
2
votes
1answer
213 views

sudo ls not showing hidden files on Linux

Today I discovered that sudo ls shows hidden files (that is, those that have names starting with .) on OS X. This surprised me so much that I asked a question about this behaviour, which I still find ...
6
votes
1answer
263 views

Why is the vi editor's copy command called Yank?

Why is the vi editor's copy command called “yank”? Is there any thing significant that can help me to remember the command name?
23
votes
2answers
488 views

Where is “export var=value” not available?

I have picked up -- probably on Usenet in the mid-1990s (!) -- that the construct export var=value is a Bashism, and that the portable expression is var=value export var I have been advocating ...
-1
votes
1answer
99 views

Who was the original author of logrotate and what year was it written?

The question started as an internal team debate. But we realized we couldn't find any information about when the original version of logrotate was authored and who wrote it.Do you have idea?
5
votes
3answers
212 views

History of Bash globbing

Is there a historical reason why Bash "globbing" and regular expressions are not identical? For example, I believe that in Bash [1-2]* matches anything that starts with a 1 or a 2 followed by anything ...
0
votes
1answer
60 views

deleting all occurences of a given command from history [closed]

I am trying to delete a specific entry in history. Clarification--by that I mean deleting all occurences containing a given command/or text. I used Aliteralmind's hxf script: :< Examples hxf ...
19
votes
5answers
5k views

What is a socket?

Could someone explain to me what a socket is? I see it in many acronyms in context of SSL, etc. Also, why is it called a socket? Is it purely because it was what a name they invented? Or was it the ...
149
votes
5answers
19k views

What's the story behind Super Cow Powers?

As we know, apt-get has Super Cow Powers and aptitude does not: $ apt-get --help | grep -i cow This APT has Super Cow Powers. $ aptitude --help | grep -i cow ...
0
votes
0answers
25 views

What are the oldest irc clients I can still use on linux ?

I have a weakness for nostalgia and some interest in Unix history, therefore I would like to know which are the oldest still usable irc clients that can be run on Linux. In this context I value age ...
20
votes
3answers
413 views

How did the Linux Kernel project track bugs in the Early Days?

We all know that Linus Torvalds created Git because of issues with Bitkeeper. What is not known (at least to me) is, how were issues/tickets/bugs tracked up until then? I tried but didn't get anything ...
11
votes
3answers
685 views

/usr/bin/ptx: Can you provide a use case or two?

I was going through the list of files included in coreutils and I was able to come up with an example of how I could personally use all of the commands provided except for ptx. Can you give one or two ...
0
votes
1answer
51 views

important changes of linux 3.1 to 3.17 [closed]

I'm doing school research project for Linux operating system and I need help with summary of version 3.1 to 3.17. The problem is, I know very little about Linux and detailed technological terms used ...
8
votes
1answer
161 views

Why does brace expansion range use two dots instead of three (ellipsis)?

I finally understood/discovered why I never got to using bash's (and also zsh's) brace expansion range properly: the syntax is {1..10} instead of what I assumed to be an ellipsis, i.e. {1...10}. May ...
2
votes
1answer
20 views

Why did “argument can be squisehd against option” prevail over “argument is always separate”?

Inspired by the recent question Why does the specific sequence of options matter for tar command?, in which the asker learned why tar -cfv test.tar *.jpg doesn't work, I'd like to ask a followup: ...
0
votes
1answer
79 views

Did Linux have a bug where reading /dev/null would crash the system?

About 10 years ago I've been told by someone that for years Linux used to crash whenever you tried to read /dev/null (ie. cat /dev/null). Is this actually true? Did such a bug exist? And if it did, ...
7
votes
1answer
548 views

Can the 25 years of development of the Linux kernel be qualified or abstracted in layman's terms? [closed]

The Linux kernel is almost 25 years old. If I had to come up with the short version on the development history of the Linux kernel since 1991(its inception date), and in partcular since 1994 (1.0.0) ...
34
votes
1answer
4k views

Why is the UNIX system call kill named 'kill'?

I'm curious about the history of the name, it seems to me that the 'kill' system call could have been named 'signal', and the 'signal' system call could have been named 'handle'. I was wondering ...
0
votes
2answers
82 views

what are considered old and powerfull commands? [closed]

I came across the terms awk and sed, awk goes once through all lines and performs a task whenever a line meets a certain condition, sed can manipulate a stream of input before it goes further to the ...
114
votes
5answers
32k views

Is Linux a Unix?

So, there are lots of different versions of Unix out there: HP-UX, AIX, BSD, etc. Linux is considered a Unix clone rather than an implementation of Unix. Are all the "real" Unices actual descendants ...
28
votes
4answers
3k views

What is GNU Info for?

I understand what GNU Info is and how to use it, but what is it for? Why does it exist in parallel to the man pages? Why not write detailed man pages rather than provide a separate utility?
1
vote
1answer
271 views

Why has '-' been chosen as the backup file suffix for certain Unix system files?

Example: /etc/group-, /etc/passwd- Is there any motivation behind choice of the - sign (e.g. easier to recognize, process, etc.)?
5
votes
1answer
160 views

Why does 'find -exec cmd {} +' need to end in '{} +'?

Preface: I understand the difference between -exec {} \; & -exec {} +. I also don't have a problem as such, I am just curious about the semantics of find. When ending the -exec argument with + ...
3
votes
1answer
70 views

Has Unix been used by accountants and other non-programmers at AT&T in the 70s and 80s?

In the short documentary, Ken Thompson and Dennis Ritchie Explain UNIX (Bell Labs) it is mentioned, that Unix is not only an OS, but also a system around which a community could form. I find ...
19
votes
1answer
718 views

What shells were used on early unix systems?

According to wikipedia, the Bourne shell was introduced in 1977 and C shell in 1978, but unix itself dates back to 1969. If you were using a unix system before 1977, what shell would you have been ...
0
votes
1answer
64 views

Syntactic differences in cp -r and how to overcome them

Let's say we are in a blank directory. Then, the following commands: mkdir dir1 cp -r dir1 dir2 Yield two (blank) directories, dir1 and dir2, where dir2 has been created as a copy of dir1. ...
6
votes
3answers
672 views

What's the rationale to have option to use power of 1000 instead of 1024 in df?

I'm curious about df -H and df -h, then man df tells me: -h, --human-readable print sizes in human readable format (e.g., 1K 234M 2G) -H, --si likewise, but use powers of ...
10
votes
2answers
189 views

Possible to see dead proccesses?

In man ps, it clearly states the different states a process can have on Linux. D Uninterruptible sleep (usually IO) R Running or runnable (on run queue) S Interruptible sleep (waiting for an ...
0
votes
1answer
134 views

What does “dd” stand for? [duplicate]

What does dd stand for? I've always referred to it colloquially as "Disk Destroyer", but what are the "official" words that make up the acronym/command? According to this link and this link it could ...
107
votes
3answers
7k views

Why not use “which”? What to use then?

When looking for the path to an executable or checking what would happen would you enter a command name in a Unix shell, there's a plethora of different utilities (which, type, command, whence, where, ...
3
votes
1answer
106 views

The history of ../ [duplicate]

I was wondering if there's a known reason behind the use of .. to represent the parent of the current directory in most operating systems. The reason I ask this question is because I think that the ...
5
votes
1answer
152 views

What is ENOANO (No Anode) intended to be used for?

This question is merely for idle curiosity, but I suspect others will be curious as well. Searching through errno.h (of Linux 2.6) I found ENOANO "No Anode". There is no sign of a "No cathode" error. ...
-3
votes
3answers
448 views

Why is “shebang” called “shebang”?

Does "shebang" mean "bang she"? Why not "hebang" as "bang he"?
3
votes
1answer
133 views

Can somebody list the earliest public source-code repositories and when they opened? [closed]

Nowadays people only know github, some people know gitlab, some people know bitbucket (mercurial) but other than that people seem to have forgotten there were others as well. I know about freshmeat ...
6
votes
3answers
222 views

When were the first graphical app installers created for Linux distributions

Having a discussion at work with a colleague, and he is claiming graphical installers for *nix environments have only been available for the last few years, but I can't find any solid information on ...