What is the hot key to show the next command of the previous command in history in Linux/bash? In Windows cmd window, let’s say I type and execute 40 commands like this: echo 1[Enter] echo 2[Enter] echo 3[Enter] … echo 40[Enter] If I decide to repeat the 40 commands again, in the same order, I …
Linux/Debian History: what Debian version became able to download and install packages from the Internet (with apt commands)? For my Linux culture: what was the first version of Debian to become able to install packages from the Internet by the mean of the apt commands? Asked By: Marc Le Bihan || Source Technically, I think …
Is there a difference between file permissions and mode? The terms "file permission" and "file mode" are often used interchangeably. However, some tools exclusively use one term or the other. Interestingly, the venerable chmod tool specifically refers to "file mode". Is there a technical or historical difference between them? Asked By: lonix || Source Technically …
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 zero. I see now we link /etc/mtab to /proc/mounts …
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 to understand what the linux kernel numbering would be at, since to my …
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 written in some markup language and then exported to HTML, …
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 question should be moved to Retrocomputing SE. Asked By: jiwopene || Source v …
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 installation/update/removal of programs; like we have today. But did the people at Bell Labs have a …
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, … , sdb1, sdb2, … are partitions (each inside the respective device). In this …
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 I try to use adb for anything (adb kill-server eg.) I get the following error: bash: …
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. To my surprise, on my Windows 98 PC, my program would create some …
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 key_f1=EOP, key_f2=EOQ, key_f3=EOR, key_f4=EOS, # gap 4 key_f5=E[15~, # …
Alpine Linux – How to prevent .ash_history from being saved? How can one prevent .ash_history from being saved at all in Alpine Linux? Asked By: user1406372 || Source Try unset HISTFILE To make the change permanent, add it to your profile. It should be /etc/profile or ~/.profile Answered By: Peregrino69 Add the following line to …
What is the historical reason for limits on file descriptors (ulimit -n) When I first borrowed an account on a UNIX system in 1990, the file limit was an astonishing 1024, so I never really saw that as a problem. Today 30 years later the (soft) limit is a measly 1024. I imagine the historical …
Is there a default clipboard history in Ubuntu? If there is, how can I access it? Is there a default clipboard history in Ubuntu 20.04 or later? If there is, how can I access it? I know there are lots of available applications for saving clipboard history in the default Ubuntu repositories. Asked By: Cherwen …
Why does `dd` have `swab` functionality The manpage for dd notes an option swab swab swap every pair of input bytes Why? Don’t ask me what I’m trying to do — I’m not doing anything in particular, I’m just scratching my head. If were going to offer swaps, why not do it for all word …
What does the letter 'u' mean in umask? Is it “user mask” or something? Wikipedia does not have details, but says the feature has been in Unix since 1978. POSIX just says it is the “file mode creation mask”. Asked By: Lassi || Source Nothing in man umask, but in bash help umask says Sets …
When did Unix stop storing passwords in clear text? When did Unix move away from storing clear text passwords in passwd? Also, when was the shadow file introduced? Asked By: ZDOSA || Source According to the History section in the wikipedia’s passwd page, Password shadowing first appeared in Unix systems with the development of SunOS …
multiline command chunks in bash history into multiple lines In Bash (as well as Bash in WSL), multiline written commands can call-back with up/down arrows correctly also built-in history command report them correctly (until I’m still logged-in in bash). But after exiting from bash and press up/down arrows, multiline commands appears each as separate entries …
Why was POSIX.1e withdrawn? The proposed POSIX.1e standard defines a few things like ACLs that are widely supported. But the proposal itself was withdrawn. How come? The only reasoning I’ve found online is this quote from http://wt.tuxomania.net/topics/1999_06_Posix_1e/: Why Posix.1e was abandoned is difficult to understand from today’s (July 2014) point of view. Solaris, Irix, Linux, …
