Linux commands: cat
A quick guide to the cat command, used to add content to a file
Similar to tail
in some way, we have cat
. Except cat
can also add content to a file, and this makes it super powerful.
In its simplest usage, cat
prints a file’s content to the standard output:
cat file
You can print the content of multiple files:
cat file1 file2
and using the output redirection operator >
you can concatenate the content of multiple files into a new file:
cat file1 file2 > file3
Using >>
you can append the content of multiple files into a new file, creating it if it does not exist:
cat file1 file2 >> file3
When watching source code files it’s great to see the line numbers, and you can have cat
print them using the -n
option:
cat -n file1
You can only add a number to non-blank lines using -b
, or you can also remove all the multiple empty lines using -s
.
cat
is often used in combination with the pipe operator |
to feed a file content as input to another command: cat file1 | anothercommand
.
This command works on Linux, macOS, WSL, and anywhere you have a UNIX environment
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