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640

Quoting Wikipedia: On Unix-like operating systems (including BSD, GNU/Linux and Mac OS X), tilde often indicates the current user's home directory: for example, if the current user's home directory is /home/bloggsj, then cd, cd ~, cd /home/bloggsj or cd $HOME are equivalent. This practice derives from the Lear-Siegler ADM-3A terminal in common ...


102

That depends on what you mean by “Unix”, and by “Linux”. UNIX is a registered trade mark of The Open Group. The trade mark has had an eventful history, and it's not completely clear that it's not genericized due to the widespread usage of “Unix” refering to Unix-like systems (see below). Currently the Open Group grants use of the trade mark to any system ...


94

The forward slash / is the delimiting character which separates directories in paths in Unix-like operating systems. This character seems to have been chosen sometime in the 1970's, and according to anecdotal sources, the reasons might be related to that the predecessor to Unix, the Multics operating system, used the > character as path separator, but the ...


77

As is often the case with obscure terms, the Jargon File has an answer: [Unix: from runcom files on the CTSS system 1962-63, via the startup script /etc/rc] Script file containing startup instructions for an application program (or an entire operating system), usually a text file containing commands of the sort that might have been invoked manually once ...


66

For distributing archives over the Internet, the following things are generally a priority: Compression ratio (i.e., how small the compressor makes the data); Decompression time (CPU requirements); Decompression memory requirements; and Compatibility (how wide-spread the decompression program is) Compression memory & CPU requirements aren't very ...


61

Apt started its life around 1997 and entered Debian officially around 1999. During its early days, Jason Gunthorpe was its main maintainer/developer. Well, apparently Jason liked cows. I don't know if he still does. :-) Anyway, I think the apt-get moo thing was added by him as a joke. The corresponding aptitude easter eggs (see below) were added later by ...


58

It appears that you are confusing two very different parts of the OS. It's understandable, because they are often referred to interchangably, but it's technically incorrect, so your question is based on a faulty premise. In order to fully explore and hopefully answer the question that you likely want to ask, a short history lesson is needed. First, there ...


47

The Jargon File has an answer which seems to agree with JanC. wheel: n. [from slang ‘big wheel’ for a powerful person] A person who has an active wheel bit...The traditional name of security group zero in BSD (to which the major system-internal users like root belong) is ‘wheel’... A wheel bit is also helpfully defined: A privilege bit that ...


46

Most of these answers are far too late to the game, as the * usage was used on Usenet and elsewhere to refer to the multiplicity of Unixoid systems. This was significantly before "the suits" even knew what was happening in cyberspace and didn't understand it if they did. I found a reference in the comp.risks archive dated May 1987 where the title ...


44

The first hierarchical file system as we know it today was designed for Multics. The design is described in “A General-Purpose File System For Secondary Storage” by R.C. Daley and P.G. Neumann. A salient characteristic of this filesystem is that a directory is a file which can be contained in a directory like any other file. The file structure forms a tree, ...


42

This is a highly simplified history of Unix and its derivatives. Windows does not figure in it because its history is essentially separate. Once upon a time operating systems were complex and unwieldy. One day in the late 1960s, Ken Thompson, Dennis Ritchie and a few of their colleagues at AT&T Bell Labs decided to write a simpler version of Multics to ...


42

Yup there were reasons. They are pronounced user and temp. passwd is similar, as is resolv.conf. Unix is an expert friendly, user antagonistic operating system. I was a student when 300 Baud modems were the norm. I was the envy of my fellow students, since I had a Silent 700 terminal from Control Data where I was working. You could see the delay from typing ...


40

This dates all the way back to the very first edition of Unix, where all the standard file names were only at most 6 characters long (think passwd), even though this version supported a whooping 8 characters in a file name. Most commands had an associated source file ending in .c (e.g. umount.c), which left only 6 characters for the base name. A 6-character ...


37

I think it stands for "diagnostic messages", as per the older man page (referenced here too). dmesg - system diagnostic messages Dmesg looks in a system buffer for recent kernel diagnostic messages and reproduces them on the standard output One of the oldest references appears to be a man page revision by Kirk McKusick dating back from 1985.


31

I'd guess lack of features - no command history, no fancy redirection, no command line editing. BSD introduced csh the C shell for those reasons. Another factor is that the Genuine Bourne Shell was only recently available in open source form. Unless you licensed it, you couldn't distribute it. That put it out of reach for free-of-cost distros, and made it ...


28

I always assumed that this feature derived from cowsay & cowthink. See the Wikipedia article on Cowsay. I've been using these for years on Fedora (I believe they predate 1999) and were used as a way to display fortunes in a more interesting way. $ fortune | cowsay ________________________________________ / It doesn't matter what you do, it only \ | ...


26

Another expansion - run control On Tue, 4 Nov 2003, goldwyn rodrigues wrote: Does anyone know what RC (in bashrc/mailrc/... ) means or how it originated? I mean, is it an acronym? If yes, what does it stand for? 'rc' stands for 'run control' and is a a convention adopted from older Unix systems. For more info see this: ...


26

Copy-paste is older than the mouse. The first unix editor, ed, had the t command to copy a bunch of lines to a different location. In vi, there are various commands to cut, yank and paste text. To copy text between files, you would save the text to copy in a temporary file and import that temporary file in the target document, e.g. with w and r in ed (:w and ...


26

In The Art of Unix Programming Eric Steven Raymond describes how this practice evolved: In the original Unix tradition, command-line options are single letters preceded by a single hyphen... The original Unix style evolved on slow ASR-33 teletypes that made terseness a virtue; thus the single-letter options. Holding down the shift key required actual ...


25

The bcd command formats the output as a punch card, like this one: From the BSD games man page: bcd ppt morse - reformat input as punch cards, paper tape or morse code The ] stands for where the holes would be. At first glance, it seems to do nothing because it's waiting for input from stdin. Try piping something into it (i.e. command | bcd) to ...


24

To trace the real story, try running man cal yourself: The Gregorian Reformation is assumed to have occurred in 1752 on the 3rd of September. By this time, most countries had recognized the reforma- tion (although a few did not recognize it until the early 1900’s.) Ten days following that date were eliminated by the reformation, so the cal- endar for ...


23

Three reasons: First, being certified as a Unix says nothing about your licensing, just your compliance to the established standards for being Unix. Second, because being Unix has nothing to do with your licensing, and everything to do with your being like Unix, an originally proprietary system, and one with a long legacy. Finally, don't mistake ...


21

For all intents and purposes, a typical modern Linux distribution (Ubuntu, Debian, Red Hat, Fedora, Slackware, etc) is a Unix, but strictly speaking, no system can claim to be Unix without being certified, so instead people say they are Unix-like. They are inspired by Unix, and carry on its culture. This also applies to BSD systems. Mac OS X is certified ...


20

The simple answer is, "they didn't copy & paste." Not in the way you understand it, anyway. The very earliest Unix systems used teletypes or dumb terminals for interactive use. These devices didn't have the powerful terminal command sets that made later innovations (!) like vi possible. (Yes, once upon a time, vi was high technology.) You therefore had ...


19

The original home directory of the root user was the root of the filesystem / (http://minnie.tuhs.org/cgi-bin/utree.pl?file=V5/etc/passwd). I think the user was indeed named after that directory. But why 'root' and not 'start' or 'origin' or something else? Well, before Ken Thompson and Dennis Ritchie wrote UNIX, they were (also at Bell Labs) developing ...


19

The reason the Info system was invented is necessity, but I guess "laziness, hubris and impatience" is an equally good explanation. The point of the GNU project was to develop a freely modifiable and freely distributible operating system and tools. The traditional Unix man system was based on the nroff/troff document formatting system from Bell Labs, which ...


19

GNU Info was designed to offer documentation that was comprehensive, hyperlinked, and possible to output to multiple formats. Man pages were available, and they were great at providing printed output. However, they were designed such that each man page had a reasonably small set of content. A man page might have the discussion on a single C function such ...


19

First of all, this question is not directly related to tar. Tar just creates an uncompressed archive, the compression is then applied later on. Gzip is known to be relatively fast when compared to LZMA2 and bzip2. If speed matters, gzip (especially the multithreaded implementation pigz) is often a good compromise between compression speed and compression ...


18

They are holdover from Unix. Memory and disk space was in short supply. Hacking out a few vowels and other abbreviations gave real savings. A few disk blocks or a few bytes could mean the difference in being able to run a program or not. (I once had to trim a program by 24 bytes before it would run.) Also as Tom noted terminal speeds were slow. 1200 ...


17

To officially be called a "Unix", an OS has to adhere to the Single UNIX Specification put out by the Open Group. OSes that are similar to Unix without actually complying with the SUS are typically called "Unix-like", which is sometimes abbreviated as Un*x or *nix (since the OSes often have -ix or -nix suffixes: Linux, Minix, IRIX, etc.). Not specifically ...



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