cat

Print and concatenate files. More information: https://www.gnu.org/software/coreutils/manual/html_node/cat-invocation.html.

• Print the contents of a file to stdout:

cat path/to/file

• Concatenate several files into an output file:

cat path/to/file1 path/to/file2 … > path/to/output_file

• Append several files to an output file:

cat path/to/file1 path/to/file2 … >> path/to/output_file

• Write stdin to a file:

cat - > path/to/file

• [n]umber all output lines:

cat -n path/to/file

• Display non-printable and whitespace characters (with M- prefix if non-ASCII):

cat -v -t -e path/to/file