Sometimes a program or software don’t start for a syntax error, and if you check the files there is nothing wrong..apparently.
There are a lot of characters that usually are not printed if you use a normal text editor, but you can easily check if they are present with your terminal and the command
As first thing let’s create a simple text file with these special characters, open a terminal and run the command:
printf 'testing\012\011\011testing\014\010\012more testing\012\011\000\013\000even more testing\012\011\011\011\012' > /tmp/testing.txt
Now if you open the file with an editor you’ll have different results.
cat will show:
$ cat /tmp/testing.txt testing testing more testing even more testing
While if you open it with nano or vim you’ll see :
testing testing^L^H more testing ^@^K^@even more testing
Now we can see some options of
cat to print special characters.
cat -T to display TAB characters as ^I
cat -T /tmp/testing.txt testing ^I^Itesting more testing ^I even more testing ^I^I^I
cat -E to display $ at end of each line
$ cat -E /tmp/testing.txt testing$ testing $ more testing$ even more testing$ $
3) Use a simple
cat -A to show up all the invisible characters:
$ cat -A /tmp/testing.txt testing$ ^I^Itesting^L^H$ more testing$ ^I^@^K^@even more testing$ ^I^I^I$
Original article : http://linuxwiki.net/2013/07/30/cat-ile-gorunmeyen-karakterleri-gormek/