Questions tagged [history]
The history of Unix systems and their main components. Please DO NOT USE this tag for shell-related questions; use "command-history" instead.
413
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3
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Why does < exist to redirect to stdin?
Question
Why do shells implement alternative means like <<<, < <(command) and < /dev/fd/* to redirect something to stdin when pipes do exist?
Example
The | way (classic pipes)
echo '...
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-1
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1
answer
33
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Why can GNU cal (the CLI calendar utility) send email messages?
The GNU cal utility has an option to send an email message to someone with its output:
--mail[=address]
Send Gcal’s output via mail program to the given address, e.g.:
--mail=esken@gmx.net
If no ...
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-2
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1
answer
64
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Was `esac` intentionally `case` just in reverse? [duplicate]
I just realized that in shell scripting esac, the closing statement for case is just case reversed. This may be a stupid question but does esac actually mean something (ie an abbreviation) or was it ...
-1
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1
answer
94
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RPG influenced names in Linux/Unix? [closed]
I have been reading about Linux and its resources recently and I have been seeing a RPG motif on a number of Linux utilities, for example Linux executables are called ELF files, the Linux manual is ...
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0
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52
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Why XKB shift levels are 1 (none), 2 (Shift), 3 (AltGr), 5, and not 0, 1, 2, 4?
XKB uses the following scheme for shift levels (as can be seen in various /usr/share/X11/xkb/ files):
level_name[Level1] = "Base";
level_name[Level2] = "Shift";
level_name[Level3] ...
3
votes
1
answer
57
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Why <sys/uio.h> called 'UIO' instead of 'VIO' [closed]
As The Open Group doc says, the <sys/uio.h> header defines the iovec structure, so why we call it Berkeley UIO.h rather than V(ector)IO.h?
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2
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1
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159
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What is the history of /etc/mtab and what updated it?
I updated an old linux boot disk with new utilities and shared libraries. It still had an empty /etc/mtab to start with, on the old disk the /etc/mtab was updated, on the new one /etc/mtab stayed ...
- 249
-1
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1
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64
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Has the linux kernel introduced incompatible changes to its "public API"?
I am trying to learn about Semantic Versioning, which states that the major version number should be bumped when an incompatible "public API" change occurs. My thought experiment is to try ...
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votes
1
answer
37
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Which software emits dates in this format between dollar signs when exporting?
Sometimes I see dates enclosed in between two $ (dollar) signs, eg. $Date: 2018/11/11 10:05:10 $ or $Date: Tuesday 06 April 2004 - 14:10:05$.
I've seen this mostly on personal homepages, most probably ...
- 103
24
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1
answer
2k
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Why does `dd` use `=` in its parameters?
Why does dd use parameters with a = (if=/dev/zero) and not the more common approach of something like -i /dev/zero?
I'm just curious if someone knows the historical reason or what the pros and cons ...
- 341
2
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2
answers
71
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Why is `-W` reserved for vendor extensions?
Why does the POSIX standard reserve the -W option for vendor extensions of the system utilities? I do not understand why the letter ‘W’ is used. ‘V’ (for vendor) could make more sense.
Maybe this ...
- 922
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2
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216
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Did Unix have a package manager?
I've looked online but couldn't get a straight answer. Plus, there are no mentions of package managers on the Unix books that I've read.
One would imagine that someone/something needed to manage the ...
- 464
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0
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45
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Why was semaphore part of Realtime rather than Pthread?
In my opinion, semaphore is a general-purpose synchronization primitive with a wide range of application. So why did the IEEE people initialy standardize it as part of Realtime extension rather than ...
- 532
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0
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22
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Alternative permissioning systems considered in the past?
I remember reading about a permissioning system other than the one we're used to in unix. If I recall correctly it was designed by someone on a team involved in the development of unix and never ...
- 3
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83
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History : For what technical reason(s) GNOME was forced to remove its icons from the desktop by default?
I'm asking a question about GNOME History.
I've red on few websites that GNOME developers where forced to remove the ability to put icons on desktop by default, for some technical reasons that I can't ...
- 907
20
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4
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4k
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What is `/dev/sda0`? Is it a standard thing?
While trying to understand this other question, I encountered /dev/sda0 being mentioned.
I have some experience in Linux and I'm used to this scheme where sda, sdb, … are devices and sda1, sda2, … , ...
- 17.9k
1
vote
1
answer
36
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HISTTIMEFORMAT messed up adb
I set up earlier this month HISTTIMEFORMAT cause I needed to see the time on some of the commands I previously used. However, I most likely messed something up with those commands, because every time ...
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0
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25
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Is there a way to timestamp the history in bash? [duplicate]
By default, history returns a list of commands and index numbers that can be used to rerun them.
Is there a way to also add the timestamp to that list?
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1
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66
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Why does the option --add_extra_groups in adduser contain underscore rather than hyphen word delimiters?
Premise
Most of the long-form options in the various *nix tools use hyphens as word separators.
Examples
from man tr:
--squeeze-repeats
--truncate-set1
from man sudo:
--preserve-env
--set-home
--...
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0
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0
answers
50
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Why is /bin merged into /usr/bin rather than the other way around? [duplicate]
I'm reading this document about the move towards merging /bin into /usr/bin:
The historical justification for a /bin, /sbin and /lib separate from /usr no longer applies today. (More on the ...
- 8,163
1
vote
1
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471
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Why is the prompt shown at the top of the terminal, rather than at the bottom?
Why am I asking this?
As you can guess, it's mostly for curiosity. But why did the curiosity spring up in my mind?
Well, there's been a moment when I noticed that I was not happy that after I'd run ...
- 1,175
23
votes
3
answers
5k
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Has Linux always separated User and Kernel space?
I was thinking back to my introduction to programming recently and remembered writing a C++ program that deliberately read and wrote to memory addresses at random. I did this to see what would happen....
- 341
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0
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677
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Why is unistd.h named the way it is?
Similar in spirit to this question about the etymology of linux commands, I'm curious about the origin of the name of unistd.h.
From the Open Group's description of unistd.h (emphasis mine):
unistd.h ...
- 119
0
votes
1
answer
57
views
When was NSS (Name Service Switch) introduced in Solaris?
I was not able to find a date or a Solaris release number... Also, beside Ultrix's svc.conf system (mentionned in NSS's Wikipedia article), did other comparable systems exist in other Unices, before ...
- 184
1
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0
answers
42
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History expansion with a string containing whitespace
I've been using unix for awhile and haven't like to use !, which, for as long as I've used unix, I've interpreted as find the last command that begins with the string following !, but it seems to not ...
- 149
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1
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52
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why no examples of video output in early computers (before desktop era) [closed]
Moved to https://retrocomputing.stackexchange.com/questions/23930/ (Retrocomputing community).
Why was the serial terminal the dominant modality for interactive computer input and output up until the ...
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1
vote
1
answer
264
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Origin of date command default US format
date seems to have a very odd default format in the US locale: Thu Jul 9 17:00:00 EDT 2020 using a space-padded day-of-month and putting the (24-hour!) time in the middle, between the month+day and ...
- 161
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0
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27
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Were there any programs besides editors that relied on on the O_NDELAY file status flag (predecessor to O_NONBLOCK)
Recently, I've been researching on the O_NONBLOCK feature specified in the standard.
From what I've seen so far, the predecessor of this flag - O_NDELAY had existed all the way back to UNIX System III....
- 532
0
votes
1
answer
116
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Deleting persistent shell history
Someone suggested this command to delete persistent shell history
history -c; >$HISTFILE
I just don't want to excute it before I know what it does exaclty, can you help?
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1
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48
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Single Unix Specification version 4 (Issue 7) moved bunch of Real-Time APIs to Base, What Next?
While reading the standard, I noticed that bunch of APIs were,
Introduced in Issue 5 for alignment with POSIX realtime APIs,
Marked for option group membership in Issue 6, and
Moved to Base in ...
- 532
15
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2
answers
2k
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What is the bsdutils package on Debian? What is a "BSD-style Unix system"?
I stumbled upon the bsdutils package in Debian. The description says:
This package contains the bare minimum of BSD utilities needed for a Debian system: logger, renice, script, scriptlive, ...
- 1,436
0
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1
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54
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Story about a complex solution vs letting it fail [closed]
I'm looking for a reference. It's a story about a team that solved a problem in a pretty complex way and the other simply let it fail, than the client would crash (or something like that) and it ...
- 127
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votes
1
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62
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how to place a text in the command line
I have a script that reads a line from a file into variable foo. The line is in fact a long command that I often use as a template. I am trying to edit and re-use this long command. How can I place $...
user492570
0
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1
answer
599
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Why does apt say "selecting previously unselected package"?
One of the most recognizable phrases of Debian-based GNU/Linux distributions is:
Selecting previously unselected package pkg.
It appears in the output of apt install pkg.
Why? What is the benefit of ...
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-1
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1
answer
107
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Any UNIX system that allow to move a file to a directory, rename file in the directory with +rw -x permission?
I'm trying to better understand how UNIX/LINUX file system works.
file system-on-linux
Compared to an inode, a directory structure contains a limited amount
of information about a file. It only holds ...
- 979
-5
votes
3
answers
109
views
Why is the command called which and not where? [closed]
Why is the command called which and not where?
Logically, you would want to search for the location of the executables, hence "where" are they, but not which.
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3
votes
0
answers
78
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Historical reason for function keys having non-consecutive key sequences in xterm
I'm using gnome-terminal as my terminal emulator, which sets TERM=xterm-256color. The key sequences sent when pressing the function keys F1, F2, … are as printed by
$ infocmp -L1 | grep _f | sort -V
...
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1
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979
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Alpine Linux - How to prevent .ash_history from being saved?
How can one prevent .ash_history from being saved at all in Alpine Linux?
0
votes
0
answers
103
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What does (or did) the name "feh" represent?
To me, the name of the feh image viewer is not memorable enough for me to recall it when I need it. I feel that if I had some context, I'd be able to remember it better.
What, if anything, does the ...
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1
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409
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Who decided the bc math library will define sine cosine and arctangent?
If you load the bc math library you get the trig functions s() and c() and a() which are sine, cosine, and arctangent respectively. Why these three functions?
I know why it's those three from the ...
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6
votes
1
answer
277
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Difference between command `command` vs command `builtin` in Shell Scripting
I understand the command command is specified in the latest POSIX standard and builtin is not. I also realize that both commands are regular builtins (i.e. they can be overwritten by user-defined ...
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13
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1
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1k
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Why do ^M and \r behave inconsistently?
Perhaps there are already answers out there that indirectly answer my question, but I've read many of them and haven't yet found a satisfactory answer to this discrepancy.
The original meaning of ...
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votes
1
answer
216
views
Why is not 'test -z =' an error after all?
I have a book that stated:
"....For example, if the shell variable symbol contains an equal sign,
look at what happens if you try to test it for zero length:
$ echo $symbol
=
$ test -z "$...
- 161
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votes
1
answer
173
views
Bash character ! of special history command
How do we change bash character ! for special history command to other direct single key character such as = ?
user464005
5
votes
5
answers
853
views
why are the definition of true and false in stdbool.h the exact opposite from the UNIX programs true and false?
stdbool.h is usually defined as:
#define false 0
#define true 1
(Sources: OpenBSD, musl, etc.)
whereas the unix program false - which just has a unsuccessful status code, is defined as:
int
main(...
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1
answer
1k
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What format does syslog() use when writing to /dev/log?
I initially thought to post this to StackOverflow because my interest was primarily from a programming focus, but after reading about the history tag (and the question it linked to), I posted it to ...
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11
votes
1
answer
574
views
What was the first file system in Linux distribution/s?
What was the first file system in Linux distribution/s?
The "parallel" to FAT (?) in Windows at the early nineties?
I want to know the name to read information about this; perhaps it was the ...
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4
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0
answers
90
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Why has ls never had a parsable option implemented? [duplicate]
So we all know you shouldn't parse ls for many reasons, mostly due to filenames allowing almost every character. However why has nobody been able to overcome this in an implementation of ls?
Many ...
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2
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1k
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How to remove up arrow to search the history?
I am not really good with Linux but I got one premade server which has Linux on it to supervise.
The OS is CentOS 7. I noticed that the up arrow allows the search of past commands (not only for the ...
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4
votes
3
answers
798
views
Were there Unix equivalents to BBSes?
During the 1980s and 1990s Bulletin Board Systems (BBS) were widely used on all kinds of computers. The BBS Documentary documents the rise and fall of the BBS subculture.
Watching this documentary ...
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