mcat

cat [OPTION]... [FILE]...

-A, --show-all
    Equivalent to -vET.

-b, --number-nonblank
    Number the non-blank output lines, starting at 1.

-e
    Equivalent to -vE.

-E, --show-ends
    Display $ at end of each line.

-n, --number
    Number all output lines, starting at 1.

-s, --squeeze-blank
    Suppress repeated empty output lines.

-t
    Equivalent to -vT.

-T, --show-tabs
    Display TAB characters as ^I.

-u
    Ignored; purely for POSIX compatibility (historical).

-v, --show-nonprinting
    Use ^ and M- notation, except for LFD and TAB.

--help
    Display a help message and exit.

--version
    Output version information and exit.

[FILE]
    The name of file to concatenate. If FILE is -, read standard input.

The `cat` command in Linux is a fundamental utility used to concatenate files and print their contents to the standard output (usually your terminal screen). It's often employed for simple tasks like viewing small files, combining multiple files into one, or appending content to an existing file. The power of `cat` lies in its simplicity and its ability to seamlessly integrate with other commands through redirection and piping. It's a cornerstone of many shell scripts and command-line workflows. While generally safe to use, be cautious when using redirection (`>`) as it can overwrite existing files without warning. `cat` is widely used, even in more complex systems administration tasks, as the basic operations are predictable. Also, it's extremely reliable as one of the most tested and mature tools.

Using redirection (`>`) with `cat` can overwrite existing files without confirmation. Be extremely careful when using `cat file1 > file1` as it will usually truncate the file, and it will be empty after the operation.

If no filename is provided or if a filename is specified as '-', `cat` reads from standard input. This allows it to be used in pipelines. For instance: `echo "Hello, world!" | cat - > output.txt`.

While not its primary purpose, `cat` can be used to create small files by redirecting standard input: `cat > newfile.txt` (Enter your text, then press Ctrl+D to end input).

The `cat` command has been a part of Unix since its early days, appearing in Version 1 Unix in 1971. It was designed to be a simple tool for concatenating and displaying files. Over the years, it has remained a fundamental utility, undergoing relatively few changes, a testament to its original design's effectiveness. Its consistent presence across Unix-like systems makes it a reliable tool for basic file manipulation.

tac(1), head(1), tail(1), less(1), more(1)