Q. Can you specify rules for naming a file name under Linux?

A. When you save a data, you nee to select a file name, you need to follow certain rules and regulation regarding the length of the name and the types of characters you include.

Rules for naming file names

The rules for naming a file names under Linux (and UNIX like oses) are as follows:

[a] The file names can be up to 255 characters (or bytes) long

[b] You cannot use all special characters, try to use:
=> Uppercase or lowercase letters
=> Digits
=> Special characters, such as: +, -, _, .

[c] File names are case-sensitive. Thus, the following file names all are different:

vivek Vivek VIVEK VIVek

[d] Try to avoid non printable and following characters in filenames:
/, >, <, ?, “, ‘, blank space

How do I show hidden files?

Use ls -a or ls -la command:
$ ls -la
$ ls -a

Use -a to see invisible file names.

How do I access filenames with spaces?

To access a filename with spaces, enclose the filename in quotes:
$ cat "my bio data.txt"
$ cd "a long dir nane"

Please note that above rules almost apply to other UNIX like operating system such as HP-UX, Solaris, FreeBSD etc.