Questions tagged [reference]

Resources, online or offline, that contain information relevant to specific subjects or would provide context for understanding Unix and GNU/Linux.

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8
votes
1answer
267 views

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 ...
0
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0answers
31 views

Is there a formal metalanguage for the Bash Reference Manual?

Reading through the Bash Reference Manual I sometimes get confused by the notation used to specify the syntax of different elements. It appears that square brackets '[<expression>]' are used to ...
0
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4answers
139 views

retrieve bash array by referencing its name as a variable

I need help with bash expansion. I want to retrieve array values, GNU bash 5.1.0. The array name shall be a variable. "Just" referencing a variable in bash. I have an array named "...
1
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0answers
58 views

Setting a user quota in ZFS which does not count snapshots

I love ZFS on Linux (RedHat 7), and users love the recovery that snapshots provide. The one problem that I have is that users will completely fill up their user quota then delete files expecting to ...
1
vote
2answers
138 views

Is a NEWLINE character at line end required by LSB (Linux Standard Base)?

Both POSIX and SUS (Single UNIX Specification) define a line as A sequence of zero or more non-<newline> characters plus a terminating <newline> character. Many distributions are more ...
1
vote
1answer
1k views

Argon2 Commands in the Terminal

I have been using Argon2 in my terminal (Debian), but I keep messing up, and I have been unable to find the manual or any other documentation that lists examples of commands that work. Could someone ...
1
vote
2answers
321 views

How linux communicate with hardware around the processor?

My question is more related to Unix/Linux development rather than administration itself. I think its directed for Unix/Linux low level system programmers rather than administrators. It will help me ...
0
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2answers
180 views

What do letters for symlink options (-P -L -H) stand for?

I've summarized a list of commands that accepts symbolic link options according to SUSv4-2018ed: cd chgrp chown chmod cp find ln ls pax rm The full list also includes their defaults and other ...
2
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2answers
136 views

I am having difficulties with back-reference in awk

Recently, I am into security logs and want to make it better way on bash-shell. I found out in awk back-references are only stored by 9. But I need to use 10 back-references. Tried awk '{print ...
0
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1answer
50 views

Sync 1 config file amongst multiple directories

Lets say I have 4 java instances running on my linux system, in separate directories, all of which have a config file named config.yml. I want to be able to edit 1 config.yml and have it copy across ...
11
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3answers
2k views

Is there any documentation for udev builtins?

The man page for udev mentions in several places that certain rules options can be used to invoke 'builtin' commands, which are apparently built in to the udev program itself. However, I haven't been ...
-1
votes
1answer
440 views

I want to extract part of a line using sed and backreference

1.The Greater Company :(Ranked 2) 5.United Taxi Service :(Ranked 3) 31.The Cacao Company :(Ranked 4) 40.Monster Inc. :(Ranked 5) 55.Afala, Industrial Strength :(Ranked 6) 60.The North Company :(...
3
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1answer
271 views

What has happened w.r.t books about linux device driver programming in the last eight years? [closed]

This is probably a silly-sounding question, but one that I think there exists an objectively right answer to which makes me compelled to ask it. I am trying to understand the fundamentals of linux ...
0
votes
2answers
223 views

What do the options after a specific command mean?

How do I understand what the various options/flags mean? For example: 1) uname -a - What does -a denote here? 2) pyang -f - What does -f denote here? I just want to understand if there is some ...
0
votes
1answer
413 views

Is the regex defining the arguments to the execve syscall in the Linux Audit standard still used?

According to the field dictionary[1] there are fields which names are defined by the following regex: a[[:digit:]+]\[.*\] I was able to find examples of fields like a4 and a5 (see 2) but it doesn't ...
2
votes
2answers
823 views

how to get the size of an indirect array in bash?

Without using eval. this wont work: astr=(a b c) str="#astr[@]" echo "${!str}"
2
votes
1answer
212 views

Is there a reference for the assembler-like output produced by `awk -W dump`?

The command awk -W dump ... produces a dump of "assembler-like" code (as shown here [link], or by reading the man). Some of the instructions are easy to guess at their meaning such as jz, which is ...
-1
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2answers
3k views

best powerpoint presenter for linux [closed]

I am using Linux Mint 17.1 rebecca. I need to use a powerpoint presenter in my laptop. Are such Powerpoint presenters are OS dependent? If so what can I use on my Linux? I am using Beamer class to ...
0
votes
1answer
90 views

Official [beginner friendly distro] reference for actual beginners [closed]

Is there official documentation for any distro accessible to complete *nix beginners? That is, aimed at the 95% least technical computer users: Assumes an already installed desktop system with ...
0
votes
1answer
505 views

Check compatibility with Linux before installing

I have a new computer, more precisely an Asus N750J, and I would like to check the compatibility of the hardware with Linux before installing (dual boot is the plan), to be prepared and prevent ...
1
vote
2answers
414 views

Cross Unix Command Reference

I am looking for a website that contains a reference between how to do things on the command line in different unix OSs. I have seen such site before, I am just unable to find it. I know such site ...
53
votes
4answers
6k views

Is there a tool/website to compare package status in different Linux distributions?

I am currently looking for a website or a tool that would allow me to compare the package state of a particular software in different Linux distributions. For instance, which version of gimp is ...
46
votes
4answers
43k views

/etc/hosts file refer to another configuration file

How can I get the /etc/hosts file to refer to another configuration file for it's list of hosts? Example /etc/hosts: ## My Hosts 127.0.0.1 localhost 255.255.255.255 broadcasthost #Other ...
3
votes
1answer
608 views

Unix dictionary add-on for Mac OS "Dictionary" app?

I've seen there's other dictionaries you can add to OS X's Dictionary app, but all I can find is spoken languages. It'd be nice to, while reading a software book, be able to right click a unix ...
32
votes
5answers
23k views

Best resources to learn bash scripting? [closed]

I've programmed in a number of languages for two years now, I mean that I know how to design and implement a decent solution for a given problem. However, bash is being a major headache to me, just ...
73
votes
6answers
5k views

Resources for portable shell programming

What resources exist for portable shell programming? The ultimate answer is to test on all targeted platforms, but that's rarely practical. The POSIX / Single UNIX specification is a start, but it ...
3
votes
1answer
236 views

EXT3 file system pre digest material

I am looking for understanding EXT3 filesystem source code. I think I need a little pre-digestion to fully understand the code. Can anyone please suggest some material(blog etc.) where I can get some ...
5
votes
6answers
3k views

How do I find a command if I don't know its name?

As a Unix beginner, I often find myself wanting to know the name of the command that achieves a particular function I'm after. How can I go about finding out the name of the command, given a ...