I would also look in the bargain bins of local book stores and check flea markets and computer swap meets.
On your specific question on the ~1
I presume you are looking at DOS prompt screens on Windows 95 and later systems.
Prior to Windows 95, all file and folder names were limited by the DOS 8.3 standard. That is, a maximum of 8 characters in the name and 3 in the extension.
Windows 95 and on create 2 versions of the file name. The new Windows version that allows more letters and spaces, and a truncated legacy DOS name.
Once a file name has more than 8 characters, or non-DOS characters in it, the DOS name becomes truncated.
Documents becomes docume~1
Documents5 in the same folder could be docume~2
The number increments when a new file with the same truncated name is added to the folder.
Chas