Today I found myself referring to: File types In Linux/Unix explained in detail. Basically:

• Regular file (-)
• Directory file (d)
• Block file (b)
• Character device file (c)
• Named pipe file or just a pipe file (p)
• Symbolic link file (l)
• Socket file (s)

Also apparently there is a thing called a Door File on Solaris, but, alas, we’re not caring about that.