Contents
How does Linux cat work?
The cat (short for “concatenate“) command is one of the most frequently used command in Linux/Unix like operating systems. cat command allows us to create single or multiple files, view contain of file, concatenate files and redirect output in terminal or files.
What does cat file1 file2 do?
Example – Using cat to redirect the contents of two files to another file. The following command redirects the contents of the files named file1 and file2 to the file named all. cat file1 file2 > all. To view the contents of the file named all we will also use the cat command as we did in the first example.
What is the difference between cat file1 and cat file1?
cat receives no arguments. Without arguments, it prints whatever’s on stdin—the contents of the file. Net result: cat file and cat < file do the same thing. As you can see, the effect is the same, that cat will read the file given; the difference is who opens the file.
What does cat file1 > file2 > file3 do?
cat file1 > file2 > file3 it first does the redirection > file2 — creating or emptying file2 and pointing stdout at it. Then it does > file 3, creating or emptying file3 and pointing stdout there. Finally it runs the command cat file1, which reads file1 and copies it to stdout.
Is there an effect on the contents of file1?
There is no effect on the contents of file1. (The same thing can, of course, be accomplished just as easily using cp command, which is used to copy files, i.e., cp file1 file2, but the above example does illustrate the great versatility of cat.)
How to redirect the output of cat to file2?
In the following example, the standard output of cat is redirected using the output redirection operator (which is represented by a rightward pointing angular bracket) to file2: cat file1 > file2. That is, the output from cat is written to file2 instead of being displayed on the monitor screen.
What happens when you use cat to create a new file?
That is, if an attempt is made to create a file by using cat and the append operator, and the new file has the same name as an existing file, the existing file is, in fact, preserved rather than overwritten, and any new text is added to the end of the existing file.