The history of Unix systems and their main components.

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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) ...
17
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1answer
599 views

At what point did the /home directory appear?

Originally in Unix, /usr was used for user (home) directories. So if I had a user named alex, my home directory would be /usr/alex. (Interestingly, Plan 9, the successor to Unix, still has user ...
4
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1answer
75 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 ...
55
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3answers
4k 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, ...
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2answers
68 views

Regex `/pattern/g` and ed `:g/pattern/`: which came first, and why `g`?

The g option (e.g. s/pattern/replacement/g) for many tools that use regex-style pattern matching and the :g command in ed/ex/vi/vim have pretty similar usage and meaning: match the given regex ...
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2answers
38 views

Why are user account on remote server called shell account

Why are user accounts on a remote server called shell account , remote account sounds like a more intuitive name what is the reason behind this very unintuitive name ???
9
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2answers
263 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 ...
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2answers
108 views

What does the “rc” stand for in /etc/rc.d? [duplicate]

Does anybody have an idea about the full form of rc.d in, for example, /etc/rc.d? It contains scripts to used to control the starting, stopping and restarting of daemons. But what exactly is the ...
1
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1answer
54 views

Is the Linux implementation of the system configuration “variable” ARG_MAX different from other system variables and is it POSIX compliant?

In the shell, as explained in this this Q&A in the context of expansion, depending on the system, the maximum length of a command's argument is initially constrained by the kernel setup. The ...
1
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1answer
43 views

What is “Charlie &” in the gecos field on OpenBSD for root?

Question: what is "Charlie &" for the root user? I didn't gave "Charlie &" for gecos field, I think I didn't gave any at all. ps.: the "/sbin/nologin" doesn't matters, I just tested ...
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What is Unix now?

As I read in Wikipedia, Unix started as a revolutionary operating system written mostly in C allowing it to be ported and used on different hardware. Descendants of Unix is mentioned next, mostly BSD. ...
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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. ...
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0answers
59 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 ...
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5answers
2k views

What aspects of Plan 9 have made their way into Unix?

Plan 9 was developed by Bell Labs as a successor to Unix. Although for various reasons it never quite materialized as such, a fair amount of development still went into Plan 9. My question is, what ...
4
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1answer
47 views

Is the historical Unix V5 tr command padding behavior of set2 different from what we consider today “classic” System V (1983-1988) behavior?

The tr command is almost 40 years old. It seemingly appeared in Unix for the first time in 1973 with Unix V4. The source for this is not available. Here is probably the second oldest available Unix ...
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2answers
8k views

What is the concept behind “tty” in linux?

Where did the terminology "tty" come from in Linux?
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5answers
8k 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 ...
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3answers
554 views

Why do we need the reboot function in different binaries?

Why do we need the reboot function in different binaries? shutdown -r and reboot Or do they differ in something?
3
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1answer
111 views

When did Automake switch to using Perl

I tried to get remove Perl from my Ubuntu machine, but found that automake not only depends on Perl but itself is a Perl program. I read somewhere this was not always the case. Today I looked in the ...
13
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2answers
386 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 ...
4
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1answer
155 views

Presentation Tools Back In The Day

I'm unsure on which Stack Exchange site this question is supposed to be asked, but since I'm especially interested in answers concerning Unix/Linux I think I'm in the right place. So: Which tools ...
5
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4answers
282 views

Does Linux use original Unix code or do they share the idea? [duplicate]

Does the Linux kernel use original Unix code or do they share the idea? He mocked me and said it's a stupid question to ask and of course they share the idea not the code. Since both are written in C, ...
464
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2answers
115k views

Why was '~' chosen to represent the home directory?

I have often wondered why the ~ represents the home directory of a user. Is there a reason behind this, or is it just some infrequently used character?
79
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3answers
10k views

What does “rc” in .bashrc stand for?

Is it "resource configuration", by any chance?
69
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3answers
10k views

Why is the root directory denoted by a / sign?

I have done some research about this on Google, but the results were cloudy. Why is the / sign used to denote the root directory. Are there any solid reasons behind it?
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5answers
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Why do /usr and /tmp directories for Linux miss vowels in their spellings?

I have often started to think about this but never found a good answer. Why are these two Unix directories not /user and /temp instead? All the other directories under root seem to be exactly what ...
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1answer
319 views

What does the “f” in fdisk stand for?

gdisk stands for GPT fdisk. cfdisk stands for curses fdisk. And so on and so forth. However, what does the original "f" in fdisk stand for? The only things I can think of would be either "files" or ...
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4answers
123 views

How do you find what keys the “erase” and “line-kill” characters are in Ubuntu?

I'm new to Unix and have bought today a copy of "The Unix Programming Environment". I'm trying out the stuff from the book. But some of them are not working as expected like : To kill a line and ...
0
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1answer
333 views

Why does halt not turn the machine off? [duplicate]

shutdown now kills everything and then powers down the machine. halt kills everything and then... there is no step 2. It will sit, running but not doing anything, until people stop arguing over ...
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4answers
4k views

Why does no one use the true Bourne shell as /bin/sh?

I've noticed that basically no system I've ever worked with has /bin/sh as a real executable. It's always a symlink to dash, bash in POSIX mode, or something similar. Why? What are the disadvantages ...
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3answers
694 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 ...
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4answers
175 views

Is the Filesystem Hierarchy Standard a UNIX standard or a GNU/Linux standard?

The Filesystem Hierarchy Standard says where to put stuff in a UNIX distribution. Is the FHS used/designed for use outside of GNU/Linux, or is it mostly limited to GNU/Linux?
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1answer
496 views

Resources System V vs BSD

I'm searching for some detailed resources about the differences of System V and BSD concepts. For example: Interprocess Communication Sockets vs TLI ... Some sort of pro/cons discussion with ...
3
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1answer
107 views

What does it mean when something says that UNIX device files are static?

I've been reading up on udev. In the "overview" section, Wikipedia states that "unlike traditional Unix systems, where the device nodes in the /dev directory have been a static set of files, the Linux ...
4
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1answer
104 views

Why does System V traditionally symlink /bin to /usr/bin?

This systemd wiki page about the /usr merge, under Myth #6, states that /bin has traditionally been a symlink to /usr/bin on System V UNIX. What is the motivation for this? For backwards ...
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4answers
763 views

How was the shift to 64 bits handled on Linux

How was the transition to 64 bits handled on Linux/Unix? The Windows world still seems to have issues with it and I'm curious how it was handled in the *nix world.
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5answers
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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 ...
5
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1answer
108 views

“globbing” (*) comes from “global command”… Huh?

According to legend, in the early days what we now call "globbing" (i.e. using expressions like e.g. *.c, ./*.p?) was supported by one certain program /etc/glob, whose name in turn derived from ...
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0answers
55 views

Where does backtick and single quote come from when denoting commands e.g. `prog'? [duplicate]

When referring to commands in tutorials, man pages, and articles I see authors use the backtick and single quote in this way: `./configure' `make' I believe I have seen gcc denote points of failure ...
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3answers
5k 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?
2
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1answer
113 views

Why has the ANSI 3.64 standard been withdrawn?

From the Wikipedia "ANSI escape code" article: The name "ANSI escape sequence" dates from 1981 when ANSI adopted ECMA-48 as the standard ANSI X3.64 (and later, in 1997, withdrew it). Does ...
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2answers
387 views

How can you log every command typed

How can you log every command someone has entered into the shell? I'm asking on both the basis of protecting yourself if you are logged into someone else's server and something breaks, or if someone ...
18
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3answers
2k views

What is the purpose of the hash command?

If you run hash it shows the path of all commands run since the hash was last reset (hash -r) [root@c04c ~]# hash hash: hash table empty [root@c04c ~]# whoami root [root@c04c ~]# hash hits ...
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1answer
2k views

Were all Unix commands re-written in Linux?

I would like to know which commands were re-written for Linux and which were retained from Unix? I'm new to Linux.
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482 views

The future of OpenSolaris

since OpenSolaris is more or less abandoned by Oracle, is there a nice alternative that implements the unique features of OSOL? ZFS is one thing, but I liked the image creation system, that let you ...
4
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2answers
84 views

Why is the default choice for -I argument '{}'?

It seems you can pass in a variable name like 'file' for -I argument of xargs, but there are a plethora of examples that use {}. Is this because of the backward compatibility? Or does it help with the ...
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1answer
146 views

Is the GNU Coreutils copied from Unix?

Linux itself is not a copy of Unix because one can argue it simply conforms to the POSIX standard. However, how about the GNU Coreutils which contains utilities like ls, cd and rm, etc...? Is there ...
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1answer
163 views

Where does this convention for quotation marks (`` …'') come from? [closed]

Frequently I get asked the question: ``K., where does this convention for quotation marks come from? You know, the one with the two grave accents introducing a quoted string and two regular ...
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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 ...
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1answer
81 views

Who was James Farber and why was he important to Unix?

I've been reading papers on Plan 9 from Bell Labs. In the paper on why Plan 9's not dead yet, around page 18, the author mentions "Farber". Googling reveals this to be a James Farber, but all I can ...