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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Where does the word GNU come from?

GNU is a Unix-like operating system. That means it is a collection of many programs: applications, libraries, developer tools, even games. The development of GNU, started in January 1984, is known ...
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1answer
96 views

How can I find out the IP address from which a user logged in?

We have two RHEL 6.4 64-bit boxes in our environment. They are accessed remotely via putty. The password of user ABC on one RHEL box is shared by multiple users. User ABC logged into server from ...
2
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1answer
29 views

What is the meaning of the mode mask names from stat(2) and chmod(2)?

The stat calls have a series of symbolic names for the various bits in the mode field. From the stat(2) manual page: The following mask values are defined for the file mode component of the st_mode ...
2
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1answer
45 views

Why is the Intel HD Graphics driver called i915?

The only references to i915 I can find are indeed to the linux kernel driver for the intel chips. Intel just seems to call them HD graphics whatever. Intel 915 seems to refer to some Pentium 4 ...
6
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1answer
133 views

How were these Linux TCP default settings decided?

I spent quite some time tracking down a problem in production recently, where a database server disappearing would cause a hang of up to 2 hours (long wait for a poll() call in the libpq client ...
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5answers
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 ...
2
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2answers
56 views

Why are certain naming conventions so inconsistent in Linux? [closed]

It seems like the general pool of logging, changelog, readme, and config files in Linux is very inconsistently named. It always makes me wonder, why didn't *nix devs decide on a common file name ...
95
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3answers
18k 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. ...
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2answers
2k views

Why is JFS so obscure?

When I first got into using Slackware years ago I quickly learned to love JFS over ext3 or reiserfs given that it was reliable and if there was an unclean shutdown, its disk checking was very very ...
37
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4answers
13k 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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3answers
737 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
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1answer
49 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 ...
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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 ...
24
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3answers
13k 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
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2answers
169 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 ...
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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 ...
33
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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
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3answers
356 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
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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?
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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 ...
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0answers
60 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 ...
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0answers
34 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.
3
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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 ...
3
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1answer
48 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
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3answers
615 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
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1answer
222 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 ...
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1answer
283 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
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2answers
515 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 ...
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1answer
107 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?
7
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3answers
262 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
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1answer
64 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
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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 ...
154
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5answers
20k 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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0answers
29 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
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3answers
445 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
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3answers
719 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
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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
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1answer
182 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
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1answer
22 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
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1answer
92 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
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1answer
612 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) ...
35
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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
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2answers
84 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 ...
115
votes
5answers
34k 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 ...
30
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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?
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1answer
276 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
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1answer
164 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
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1answer
75 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
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1answer
719 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
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1answer
67 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. ...