cat - concatenate files to stdout
$ cat [file...]This program passes contents of specified files to standard output, in the specified order. If no file is specified, or it is -, it defaults to standard input.
file: Files to print# Display a single file
$ cat README.md
# SerenityOS
Graphical Unix-like operating system for x86 computers.
...
# Display standard input
$ cat
aaa
aaa
bbb
bbb^C
# Display ls output where each file is in separate line
$ ls | cat
Desktop
Documents
Downloads
README.md
Source
js-tests
tests
web-tests
# Display multiple files
$ echo 123 > test.txt
$ echo 456 > test2.txt
cat test.txt test2.txt
123
456