Linux cat source code

Где лежит cat.c в Linux?

Где лежит файл cat.c в Linux? Хотел посмотреть его код, а не нашел.

Re: Где лежит cat.c в Linux?

Re: Где лежит cat.c в Linux?

Если в ядре нет кода, то откуда linux понимает такую команду. Чё-та не верится что нет исходников таких в ядре

Re: Где лежит cat.c в Linux?

Посмотри в пакете coreutils (coreutils-dev)

Re: Где лежит cat.c в Linux?

Утилиты пользователя к ядру отношения не имеют.

Re: Где лежит cat.c в Linux?

Оттуда, что cat лежит в $(which cat), ядру пофик на команды. А вообще, если не ошибаюсь, в K&R есть примерный исходный код cat

Re: Где лежит cat.c в Linux?

по-мойму в каждом уважающем себя дистрибутиве есть поиск по содержимому пакетов. в Debian — dpkg -S или apt-file.

Re: Где лежит cat.c в Linux?

Re: Где лежит cat.c в Linux?

вы на гугле забанены? первая ссылка по запросу ‘»dpkg -S» redhat’ выдает http://www.pixelbeat.org/docs/packaging.html

rpm -q -f /path/file

Re: Где лежит cat.c в Linux?

Re: Где лежит cat.c в Linux?

Re: Где лежит cat.c в Linux?

> Если в ядре нет кода, то откуда linux понимает такую команду. Чё-та не верится что нет исходников таких в ядре

Предлагаю проспаться и протрезветь.

При чём тут ядро?!

Re: Где лежит cat.c в Linux?

Re: Где лежит cat.c в Linux?

> Почему именно 8192?

It’s a Kind of Magic:)

Re: Где лежит cat.c в Linux?

Re: Где лежит cat.c в Linux?

$ factor 8192 >8192: 2 2 2 2 2 2 2 2 2 2 2 2 2

Это и так ясно. Почему тогда не 4096? Почему не другая степень двойки? Почему степень двойки — вроде как понятно. Хотя не очень.

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Linux cat Command

This article will focus on all useful aspects of “cat” commands. However, this command is also highly suitable for performing some really tricky tasks in scripting.

Cat usage

The binary is located in the “/usr/bin/cat” location.

This tool is a part of the GNU coreutils package. The source code of GNU coreutils is readily available on GitHub.

• Display file content

I’ve created a text file with random data. The data was grabbed from random bytes generator by Random.org.

Let’s check out the content of the file using “cat”.

The “cat” tool can print the output of any file that the current user has the permission to read. For example, “/etc/passwd” file is accessible to any user to just “read”.

However, it can’t access something that only “root” has permission to. In this case, the file “sudo_random.txt” is the exact copy of the original “random.txt” but only “root” having access to it.

• Contents of multiple files

The structure of this command is similar to the basic usage of “cat”. All you have to do is pass the files with their location one by one.

It can be performed in a different manner as well.

• Create a file using “cat”

It’s not actually a core function of the “cat” command. However, it can serve the task quite easily.

After running this command, you can type whatever you want and then, press “Ctrl + D”. It will write the user input to the file.

If you want just a blank file, then press “Ctrl + D” without typing anything.

If you’re accessing a file that’s too large, then scrolling through the output of “cat” command becomes really, really annoying. In that case, we can redirect the output to “more” or “less” for more convenience.

For example, the demo text file I’m using is quite big. If you’re working with log files, this is a familiar scenario. In such situations, “more” or “less” can offer significant value. The “more” tool displays the output one page at a time. The “less” tool is similar to “more” but with additional features. However, we’re not going to dive deeper into these tools.

Let’s redirect the output of “cat” to “more”.

To quit the view, press Q.

For pipelining the output to “less”, use this command.

Same as “more”, quit by pressing Q.

When “cat” displays the content, it doesn’t show the numbering of the lines. Use the “-n” flag.

You can use this with “more” or “less” as well.

When using “-n” flag, “cat” shows line numbering for all the lines, including empty and non-empty ones. However, using the “-b” flag, “cat” will only number the non-empty ones.

Note: This flag will override “-n” by default.

How about replacing the “end of line” with $?

Here, “cat” prints the output with both the line number and replacing the “end of line” with $ symbol.

Using the following command, you can swap the tab spaces with “^I” character.

Within the chaos of characters, it’s hard to find out those tabs, right?

• Suppress repeated empty lines

In some cases, there could be multiple empty lines in-between the content. In that case, use “-s” flag to eliminate the empty lines in the output.

• Redirect output

We can use the standard output format to redirect the output of any “cat” command to a file. If the file already exists, it will be overwritten. Otherwise, it’ll be created.

This command can also be used to merge the contents of multiple files into one single file.

If you don’t want to overwrite the content of an existing file, you can append the “cat” output at the end.

Just like before, it’s possible to append the content of multiple files into the same file.

• Showing non-printing characters

A text file isn’t just all the showing characters. There are a number of hidden characters that are non-printable. If you need to show them, use the “-v” flag.

“cat” alternative

While “cat” is a crucial part of every single UNIX/Linux system, there are reliable alternatives to print the content of a text file. Here, I’ll be showing off “bat” – a “cat” clone with wings!

The “bat” tool is readily available on all the major Linux distros. It comes up with its own style. You can customize the output with themes, pager, formats and a lot more.

Let’s see how “bat” shows the content of my demo file.

As you can see, “bat” shows line number and the file name by default. Moreover, it uses the “more”-like scrolling by default. For getting out of the window, press Q.

Let’s see if “bat” successfully makes a copy of the file.

Using “bat”, it’s possible to perform all the “cat” functions without any trouble. For complete documentation, check out the official bat GitHub page.

Final thoughts

There are plenty of scenarios where “cat” and “bat” can be useful. For all the available options, there’s nothing better than the man and info pages.

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Linux Cat Source Code

coreutils/cat.c at master · coreutils/coreutils · GitHub

7/8/2021 · /* Cat the file behind INPUT_DESC to the file behind OUTPUT_DESC. Return true if successful. Called if any option more than -u was specified. A newline character is always put at the end of the buffer, to make: an explicit test for buffer end unnecessary. */ static bool: cat (/* Pointer to the beginning of the input buffer. */ char *inbuf,

bash — View source for standard Linux commands e.g. …

You can see assembly code of /bin/cat with: objdump -d /bin/cat. Then analyze it and see what command can be launch. Another way of approaching is strings /bin/cat, it is usefull make a initial idea and then reverse it. You can get the source code of every linux command online anyway 😀

where can I donwland the source code of ‘cat’?

17/8/2005 · How to convert Assembly code to «C» source code: ssg14j: Programming: 2: 08-01-2005 12:48 PM: All this source code: W0bbles: Linux — Software: 1: 02-12-2005 08:32 PM: source code: acrors: Fedora: 1: 09-29-2004 10:23 PM: source code: vishal_iet: Linux — General: 5: 12-26-2002 11:37 AM: Source Code: juniorone: Linux — Newbie: 1: 02-09-2002 12:27 PM

The Cat Command in Linux – Concatenation Explained …

5/5/2020 · Cat in Linux stands for concatenation (to merge things together) and is one of the most useful and versatile Linux commands. While not exactly as cute and cuddly as a real cat, the Linux cat command can be used to support a number of operations utilizing strings, files, and output. The cat command has three primary purposes involving text files: Create

Cat command in Linux with examples — GeeksforGeeks

14/9/2017 · $ cat >newfile Output Will create and a file named newfile 5) Copy the contents of one file to another file. Command: $cat [filename-whose-contents-is-to-be-copied] > [destination-filename] Output The content will be copied in destination file 6) Cat command can suppress repeated empty lines in output Command: $cat -s geeks.txt Output

Source Code of the Linux commands

14/11/2006 · So if I modify for example «cat» can I apply it to the system so if I open a terminal to see the results with the «new» cat. Yes, you can, but you might then find you have broken some aspects of your system. Linux has many bash scripts, some of which might rely on cat behaving in the usual manner.

Open Source Code Archive · GitHub

C 0 0 0 0 Updated on Jan 28. cat-s60-gpl-sources. CAT‘s open source code release for the S60 smartphone. C 0 0 0 0 Updated on Jan 28. telekom-speedport-w500v. German Telekom’s Open Source Code release for the Speedport W500V ADSL router. C 0 0 0 0 Updated on Jan 18. zyxel-o2-homebox-6641. «Open Source Package» release for the Zyxel VMG7947-B40A aka.

linux — How do I read the source code of shell …

To install git on your Ubuntu machine, you should use apt-get (git is not included in the standard Ubuntu installation): sudo apt-get install git. Truth to be told, here you can find specific source for the lscommand: http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/ls.c.

Do the common programs (for example: «ls», «cat») in …

15/3/2019 · The short answer is:Not necessarily. The source code of common programs such as ls, cat, echo, kill, etc. depend on what userlandthey come from. In other words, the userland your system uses. The most common userland used with the Linux kernel is GNU — hence the name GNU/Linux.

Get Source Code for any Linux Command — The Geek …

19/2/2010 · Question: How do I get source code of any Linux command? Answer: For Debian family Linux distributions, you can get source code for any Linux commands using one of the two methods mentioned below. $ cat /etc/apt/sources.list deb-src http://ftp.de.debian.org/debian lenny main $ apt-get update For example, to get source

cat command in Linux/Unix | view file

cat command in Linux/Unix. Linux cat command. cat command is used to display the content of text files and to combine several files to one file. The cat command does not accept directories. cat command syntax $ cat [options] file1 [file2. ] cat command options. cat command main options:

Linux source code (v5.14.9) — Bootlin

Elixir Cross Referencer — Explore source code in your browser — Particularly useful for the Linux kernel and other low-level projects in C/C++ (bootloaders, C libraries. )

cat.c — Busybox source code (0.43) — Bootlin

Elixir Cross Referencer — Explore source code in your browser — Particularly useful for the Linux kernel and other low-level projects in C/C++ (bootloaders, C libraries. ) Boot …

The source code to GNU cp, mv, ls, pwd, uname, …

The source code to GNU cp, mv, ls, pwd, uname, chmod, cat, ln. A bit messy and very enlightening.

How To Use cat Command In Linux / UNIX — nixCraft

9/2/2010 · The cat command can also be used to create a new file and transfer to it the data from an existing file. To make copy of. $ cat oldfile.txt > newfile.txt. To output file1’s contents, then standard input, then file2’s contents, enter: $ cat file1 — file2. A hyphen indicates that input is taken from the keyboard.

source command in Linux with Examples — GeeksforGeeks

16/4/2019 · Each command enlisted in the file will be executed line by line. Example 2: To pass a path_name of a file as an argument where, /home/sc/sourcefolder/ is the file directory here. The content of the file is written below: echo ” Hello, Welcome to Geeksforgeeks”. echo “current directory is:”. pwd.

cat Command in Linux / Unix with examples — nixCraft

27/2/2012 · Unix is the best. . You need to press [CTRL] + [D] i.e. hold the control key down, then tap d. The > symbol tells the Unix / Linux system that what is typed is to be stored into the file called foo.txt (see stdout for more information). To view a file you use cat command as follows: cat foo.txt.

Add Kali Linux official repositories to sources.list .

26/1/2020 · Login as root or user to your machine and launch a terminal. In the terminal, check the current list of apt repositories present in the system. $ cat /etc/apt/sources.list. If no APT repositories are present, paste the code below to add them.

The GNU Netcat — Official homepage

Although the project development is marked as beta, GNU Netcat is already enough stable for everyday use. Goals of this project are full compatibility with the original nc 1.10 that is widely used, and portability.GNU Netcat should compile and work without changes on the following hosts:

xclock -mode cat | Code From Above

Since then, the source code has been changed very little, primarily in response to more strict C compilers. Today, the source compiles and runs on OS X, Linux, and Cygwin, with the only changes necessary being header and library paths in the Makefile for OS X. Yep, 30 years of legacy in an industry and science noted for its fast-paced evolution.

Take a break at the Linux command line with nyancat .

6/12/2018 · Take a break at the Linux command line with Nyan Cat. Rainbows, Pop-Tarts, . be careful about installing applications from untrusted sources or compiling and running any piece code you find online, . You can find the source for nyancat on GitHub under an NCSA open source license.

A Unix/Linux ‘cat’ function in Scala | alvinalexander.com

12/9/2013 · A Unix/Linux ‘cat‘ function in Scala. By Alvin Alexander. Last updated: June 6, 2016. As a quick note today, the following Scala function is more or less the same as the Unix cat command: package iotests object Cat extends App < import HIO.using import scala.io.Source /** * `getLines` returns an iterator who returns lines (NOT including newline .

How to Convert Files to UTF-8 Encoding in Linux

2/11/2016 · List Coded Charsets in Linux Convert Files from UTF-8 to ASCII Encoding. Next, we will learn how to convert from one encoding scheme to another. The command below converts from ISO-8859-1 to UTF-8 encoding.. Consider a file named input.file which contains the characters:. Let us start by checking the encoding of the characters in the file and then view the file contents.

Linux Kernel Development – Creating a Proc file and .

20/3/2018 · After some debugging, the count parameter value is 131702 when reading with the “cat” command. 131702 is greater than the 100 defined for the BUFSIZE causing the read function to return -EFAULT. I changed the logic to make sure there is enough space to hold the output for reading in ‘buf’ and only copy from ‘buf’ to ‘ubuf’ for no more than the count size.

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