10 Linux Cat Command Examples for Beginners
Jan 11, · UNIX / Linux cat command examples - Explains how to use the cat command under Linux or Unix like operating systems for various purpose such as displaying the file, concatenate, creating the file and much more. The “cat” command in Bash stands for “concatenate”. This command is very frequently used for viewing, creating, and appending files in Linux. Today, we will explain to you the usage of this command in Bash in Linux Mint 20 by sharing some examples. Method of Using the “cat” Command in Bash.
If you a regular Linux command line user, I am sure you must have used the cat command. The tool is mostly used for displaying contents of a file, although it provides many other small but useful features. In this article, we will discuss the cat command in detail, explaining some of its key features. Please note that all examples mentioned in this tutorial have been tested on Ubuntu Following are 10 points that'll give you a good idea about catincluding how it works and what features it provides:.
The cat command allows you to view contents of a file on the standard output stdout. This can be done in the following way:. The tool also allows you to display contents of multiple files in one go. If you want, you can also display contents of a file with line numbers printed at the beginning of each line.
If you want, you can also create a new file, and fill it with information using a single cat command. Here's how you do it:.
When run, the command requires you to enter the information on the terminal. To cross-verify the existence of the file as well as check what information it contains, I used the following command:. You can also use cat to copy the contents of one file to another file. If you want, you can also make cat highlight the end of lines. If you want, you can also make the cat command suppress repeated empty lines in output.
This can be done by using the -s command line option. The first command in the above screenshot shows all the empty lines that are there in the file. But due to the -s command line option we used in the second cat command, the repeated empty lines got suppressed.
If you want, you can also make the cat command display non-printable characters. This can be done using the -v command line option.
As you can see in the above screenshot, the what is lead and lag indicators command normally displayed contents of the file containing non-printable characters. But when we used the -v option, those characters were displayed in a special notation the option uses. In case, you need to use the -v, -E and -T option together, then instead of writing -vET in the command, you can just use the -A command line option.
As you can see in the screenshot above, the first command shows the file file Those lines contain tabs as well as some non-printable characters. We've covered most of the cat command options here, so practicing them should give you how to use cat linux pretty good idea about the how to convert a cda file to mp3. Do try them out, and once done, head over to the command's man page to learn more about it.
Pretty much every command that cat is used to create a stdin stream would be faster, less resources used, if the next command just read the file directly.
Books and online examples commonly show. This is wasteful. I run into those about once a year. This feature is only available to subscribers. Get your subscription here. Log in or Sign up.
On this page Linux cat command 1. How to view contents of a file using cat 2. How to display multiple files using cat 3. How to display contents of file with line numbers 4. How to create file using cat command 5.
How to copy the contents of one file to another file 6. How to make cat highlight line-ends 7. How to make cat suppress repeated empty lines 8. How to make cat display non printing characters The -A option. Suggested articles. Some useful options above. Your name or email address: Do you already have an account? No, create an account now. Yes, my password is: Forgot your password?
2. How to display multiple files using cat
Jul 13, · If you have worked in Linux, you surely have seen a code snippet that uses the cat command. Cat is short for concatenate. This command displays the contents of one or more files without having to open the file for editing. In this article, learn how to use the cat command in Linux. Jan 11, · The cat (short for “concatenate“) command is one of the most frequently used command in Linux/Unix like operating freenicedating.com command allows us to create single or multiple files, view contain of file, concatenate files and redirect output in terminal or files. In this article, we are going to find out handy use of cat commands with their examples in Linux. Linux cat command. The tool's man page describes it as: cat - concatenate files and print on the standard output. Following are 10 points that'll give you a good idea about cat, including how it works and what features it provides.
The name is derived from its function to con cat enate files. The Single Unix Specification defines the operation of cat to read files in the sequence given in its arguments, writing their contents to the standard output in the same sequence. The specification mandates the support of one option flag, u for unbuffered output, meaning that each byte is written after it has been read.
Some operating systems, like the ones using GNU Core Utilities , do this by default and ignore the flag. If one of the input filenames is specified as a single hyphen - , then cat reads from standard input at that point in the sequence.
If no files are specified, cat reads from standard input only. Example of some cat options: . As such, its two main use cases are text files and certain format-compatible types of binary files. For many structured binary data sets, the resulting combined file may not be valid; for example, if a file has a unique header or footer, the result will spuriously duplicate these.
However, for some multimedia digital container formats , the resulting file is valid, and so cat provides an effective means of appending files. Video streams can be a significant example of files that cat can concatenate without issue, e.
The Jargon File version 4. Among Unix fans, cat 1 is considered an excellent example of user-interface design, because it delivers the file contents without such verbosity as spacing or headers between the files, and because it does not require the files to consist of lines of text, but works with any sort of data. Among Unix critics, cat 1 is considered the canonical example of bad user-interface design, because of its woefully unobvious name.
It is far more often used to blast a single file to standard output than to concatenate two or more files. The name cat for the former operation is just as unintuitive as, say, LISP 's cdr. Useless use of cat UUOC is common Unix jargon for command line constructs that only provide a function of convenience to the user. Example of a common cat abuse is given in the award:.
This can be rewritten using redirection of stdin instead, in either of the following forms the first is more traditional :. Beyond other benefits, the input redirection forms allow command to perform random access on the file, whereas the cat examples do not. This is because the redirection form opens the file as the stdin file descriptor which command can fully access, while the cat form simply provides the data as a stream of bytes. Another common case where cat is unnecessary is where a command defaults to operating on stdin, but will read from a file, if the filename is given as an argument.
This is the case for many common commands; the following examples. A common interactive use of cat for a single file is to output the content of a file to standard output. However, if the output is piped or redirected, cat is unnecessary. A cat written with UUOC might still be preferred for readability reasons, as reading a piped stream left-to-right might be easier to conceptualize.
It is named by analogy with cat. From Wikipedia, the free encyclopedia. For other uses of cat, see Cat disambiguation and Cat. Bell Labs. Retrieved Unix command-line interface programs and shell builtins. GNU Core Utilities command-line interface programs.
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Download as PDF Printable version. Ken Thompson , Dennis Ritchie. November 3, ; 49 years ago Unix , Unix-like , Plan 9 , Inferno. Create a file called newfile. The text will be in file newfile. Concatenate the files, sort the complete set of lines, and write the output to a newly created file.
The Wikibook Guide to Unix has a page on the topic of: Commands.
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