Copy one file contents to another file in Linux

The cp commands basic syntax is:
cp file_name new_file_name
cp [options] file_name new_file_name
cp original_name new_name

Please note that when a copy is made of a file, the copy must have a different name than the original. For example, the following is a valid example:
cp file1 file2
However, the following would fail:
cp nixcraft.txt nixcraft.txt
Sample outputs:

cp: 'nixcraft.txt' and 'nixcraft.txt' are the same file

However, a file named nixcraft.txt could be copied with the same name into another directory:
cp -v nixcraft.txt /tmp/
File names are case sensitive too. It means following example should work:
cp nixcraft.txt NIXCRAFT.txt
ls -l nixcraft.txt NIXCRAFT.txt
Sample outputs:

-rw-rw-r--. 1 vivek vivek 6 Jan 20 18:12 nixcraft.txt
-rw-rw-r--. 1 vivek vivek 6 Jan 20 18:12 NIXCRAFT.txt

Linux copy file to another file

Let us create a new file in Linux named foo.txt:
echo "This is a test" > foo.txt
Next copy foo.txt as bar.txt, run:
cp foo.txt bar.txt
Verify it with help of ls command:
ls -l foo.txt
ls -l bar.txt
To see cp command progress and verbose output, pass the -v command option to cp:
cp -v foo.txt bar.txt
Update the original foo.txt:
echo "Another line" >> foo.txt
Use the cat command to see both files:
cat foo.txt
cat bar.txt

Copy content of one file to another file

Say you want to copy all files from /home/vivek/project/ to /home/vivek/backups/, run:
cp -av /home/vivek/project/ /home/vivek/backups/
Now, we can make changes in /home/vivek/project/ directory.
Where,

1. -a : Archive mode i.e. copy all files and directories recursively
2. -v : Verbose mode
3. -r : Recursive mode in Linux for cp command

Conclusion

Writing contents of a file to another file is easy in Linux. Simply use:
cp -v filename newname
For more information see cp command man page by typing the following [nixmd name=”man”]:
man cp