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

learn more… | top users | synonyms

0
votes
1answer
35 views

Functionality of first version Linux? [on hold]

When Linus posted the very first original version of Linux (that he sent to a mailing list) - how much functionality did it have? What could it do and what couldn't it? I supposed that it didn't have ...
1
vote
1answer
37 views

why isn't there a historical pretty log of your upgrades, downgrades and package purges in Debian?

I wanted to lookup history of my recent updates/upgrades, package purges and found out that other than aptitude and ugly dpkg.log, there doesn't seem to be anything else which does the same. See ...
0
votes
0answers
31 views

When was pipelining introduced?

I understand early versions of Unix were licenced from AT&T to Universities and ran on PDP computers. I read in Tanenbaum's book (operating systems) that the first versions of Unix were only a ...
3
votes
1answer
51 views

When did bash's shopt huponexit start defaulting to off?

On Monday morning, I logged into a box with ssh and ran the following command: tail -f /var/log/foo/bar.log | grep something_interesting & At some point later in the day, I logged out by ...
3
votes
3answers
133 views

When was the UNIX single-user vs multi-user modes distinction first introduced?

Practically if not actually every single UNIX-like operating system today makes the distinction between multi-user and single-user modes. Single user mode is generally intended for low-level system ...
50
votes
5answers
5k 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 ...
7
votes
1answer
88 views

What is the historical origin of CTRL + P for up and CTRL + N for down?

I am a moderately experienced vim user, who is now beginning to use GNU emacs. At about the same time as I learned that Ctrl-p and Ctrl-n are the default for up and down in emacs, I also learned they ...
1
vote
2answers
407 views

Why are HTTP operations usually written in all caps? [closed]

I'm looking for the history of this. Why do we usually write HTTP POST or OPTIONS operations in all caps?
6
votes
1answer
424 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. ...
1
vote
4answers
63 views

Why is it find dir -name file and not find -n dir file?

I've searched around for this but I couldn't find anything on it. I've always wanted to know, why is it that most other built in bash commands have the format of command -flag arg1 arg2, i.e. cp -r ...
7
votes
1answer
102 views

Why does 8250 UART driver not wake up TTY if more than 256 characters are pending?

What is the motivation of this if-condition in void serial8250_tx_chars(struct uart_8250_port *up)? if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); It has been ...
0
votes
3answers
64 views

Comparing integers: arithmetic expression or conditional expression

In Bash, two integers can be compared using conditional expression arg1 OP arg2 OP is one of ‘-eq’, ‘-ne’, ‘-lt’, ‘-le’, ‘-gt’, or ‘-ge’. These arithmetic binary operators return true if ...
-6
votes
1answer
79 views

Why does GNU say it is “Not Unix”? [closed]

I use Fedora. Today I found GNU (on the web) about which I didn't know till yesterday. I knew that GNU is a Unix-like operating system that is free software but I didn't get why they say GNU's "Not ...
2
votes
3answers
739 views

Why can't Korn Shell do ctrl-r?

If I use PC-BSD with the default shell (Korn) then Ctrl+r doesn't work. Why won't it work? Ctrl-r was introduced to search your history in the late 1970s or early 80s and my BSD still can't do it ...
2
votes
1answer
52 views

Unix vs OS360 (History)

I read the history of Unix operating system and also read the original Unix paper by Thompson and Ritchie. In their paper they mention some key features which Unix uses. Some terminologies including ...
-9
votes
2answers
142 views

What is the name of an animal used as a logo by the GNU Project? [closed]

What is the name of an animal used as a logo by the GNU Project (gnu.org)? And why was this animal chosen to represent the project?
10
votes
1answer
149 views

Why is the circumflex/caret character used as a symbol for Ctrl?

I started using the Linux console a long time ago but I never questioned myself about the circumflex aka caret character (^). I'd like to ask why it's used as a replacement for the word Ctrl. I ...
122
votes
4answers
28k 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. ...
0
votes
1answer
16 views

What was xhbin?

I've googled, searched Unix & Linux Stack Exchange, and... well, there's not really much else I can do, is there? I was browsing some quines in various shell languages, and I came upon the ...
2
votes
1answer
30 views

Behold System V; what about systems I-IV?

System V (by AT&T) is the ancestral Unix, and I have used it. But I have never read or heard anything about systems I-IV, other than they existed once upon a time in the dim past. How effective ...
3
votes
1answer
89 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. ...
1
vote
2answers
57 views

Why was shar written if tar already existed?

According to the BSD man pages, tar first appeared in Version 7 UNIX in 1979, but shar first appeared in 4.4BSD, which was released in 1994. What were the perceived advantages to shar at the time? ...
2
votes
0answers
45 views

put string to commandline

I am making a bashfunction that show a menu binded to pgdown to browse through a a window which list my history (like 4dos/4nt etcetera). I have made so one line is always highlighted. $pos is ...
1
vote
1answer
56 views

'revert' bash to searching correct history file [closed]

I hope this makes sense as I explain it, so please bear with me! I recently decided it would be a good idea to start backing up my history, and did so with the following added to .bashrc: export ...
30
votes
6answers
9k views

Single dashes `-` for single-character options, but double dashes `--` for words?

Where did the convention of using single dashes for letters and doubles dashes for words come from and why is continued to be used? For example if I type in ls --help, you see: -a, --all ...
33
votes
2answers
2k views

Oldest binary working on Linux?

In a discussion on backwards-compatibility in Linux kernel and GUI ABIs, Alan Cox notes that "my 3.6rc kernel will still run a Rogue binary built in 1992. X is back compatible to apps far older than ...
20
votes
6answers
9k 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 ...
25
votes
2answers
891 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
vote
2answers
71 views

Why doesn't unix filesystem store creation time of a file? [duplicate]

Is there any historic reason? Stat stores last accessed time, last modified time and last changed time , but not the creation time! Isn't that important information. I can't understand why the ...
51
votes
5answers
23k 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 ...
1
vote
1answer
50 views

Why is uninterruptible sleep indicated by 'D'?

From "man ps": R = Running or Runnable S = interruptable Sleep T = sTopped Z = Zombie D = uninterruptible sleep (usually IO) Where does this D come from?
31
votes
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.
26
votes
4answers
2k views

Does vi silently add a newline (LF) at the end of file?

I have trouble understanding a weird behavior: vi seems to add a newline (ASCII: LF, as it is a Unix (AIX) system) at the end of the file, when I did NOT specifically type it. I edit the file as such ...
29
votes
5answers
2k views

What is the point of mv -f?

The GNU Coreutils manual for mv says: -f --force Do not prompt the user before removing a destination file. However, this already seems to be the default behaviour for mv, so the -f option appears ...
30
votes
3answers
20k 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?
45
votes
2answers
4k views

Why is rm allowed to delete a file under ownership of a different user?

From the post Why can rm remove read-only files? I understand that rm just needs write permission on directory to remove the file. But I find it hard to digest the behaviour where we can easily delete ...
2
votes
1answer
47 views

Why is the xargs -i option deprecated?

I was reading the Linux man page for xargs recently, and it appears that the -i option is deprecated. To quote from the documentation: -i[replace-str], --replace[=replace-str] This ...
0
votes
3answers
118 views

get IP address who modified a file

I am looking a way to to get the history of a file, like the modification date, who modified this file (ip address or username), the changed lines Is there a way to get the IP address or username of ...
74
votes
9answers
5k views

On what systems is //foo/bar different from /foo/bar?

Throughout the POSIX specification, there's provision (1, 2, 3...) to allow implementations to treat a path starting with two / specially. A POSIX application (an application written to the POSIX ...
4
votes
1answer
119 views

Origin of /etc/termcap linux entry

Why is there a type of $TERM called linux described in /etc/termcap? Why and when was it created and what's the point of it? Couldn't we just stay with vt-generic? Is linux just a customary name and a ...
4
votes
2answers
87 views

Purpose of find command's default size unit 512 bytes

The find command allows you to search by size, which you can specify using units spelled out in the man page: File uses n units of space. The following suffixes can be used: `b' for 512-byte ...
112
votes
6answers
40k views

Where did the “wheel” group get its name?

The wheel group on *nix computers typically refers to the group with some sort of root-like access. I've heard that on some *nixes it's the group of users with the right to run su, but on Linux that ...
38
votes
4answers
5k views

Is the shell ksh93 dead?

On 10/1/2013 Glenn Fowler posted this to the ast-users mailing list: As has been pointed out several times on the AST and UWIN lists, AT&T gives very little support to OpenSouce software, ...
0
votes
0answers
23 views

Save history to separate file with time-stamp and who did the action

I'm looking for a solution to capture all Linux commands to some file, there are many solutions but I prefer to capture all History to some file. I want it to include : "time-stamp" "Server-name" ...
1
vote
1answer
109 views

History of UNIX not including current directory in $PATH

In the UNIX world, it's well understood that you need to prefix binaries in the current directory with ./ in order to run them: . is not in $PATH by default. This is to avoid evil binaries overriding ...
186
votes
5answers
32k 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
4answers
145 views

How to run Unix?

I always wanted to try Unix but I can't seem to find an ISO file or somewhere to buy it. Is Unix published for the whole wide world to use or is it a special OS only for high-class servers, mainframes ...
656
votes
2answers
136k views

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

I have often wondered why the ~ (tilde) represents the home directory of a user. Is there a reason behind this, or is it just some infrequently used character?
11
votes
2answers
708 views

Is there a reason why the first element of a Zsh array is indexed by 1 instead of 0?

From my experience with modern programming and scripting languages, I believe most programmers are generally accustomed to referring to the first element of an array by 0 as index. Are there any ...
48
votes
6answers
3k views

Is there any reason to have a shebang pointing at /bin/sh rather than /bin/bash?

In most shell scripts I've seen (besides ones I haven't written myself), I noticed that the shebang is set to #!/bin/sh. This doesn't really surprise me on older scripts, but it's there on fairly new ...