Generate a random ASCII string (40 printable characters without empty spaces)
$ cat /dev/urandom | tr -dc '[:graph:]' | head -c 40
OR
$ cat /dev/urandom | tr -dc '[:alnum:][:punct:]' | head -c 40
[:lower:] All lower case letters abcdefghijklmnopqrstuvwxyz
[:upper:] All upper case letters ABCDEFGHIJKLMNOPQRSTUVWXYZ
[:alpha:] All letters
[:digit:] All digits 0123456789
[:alnum:] All letters and digits
[:punct:] All punctuation characters !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~
[:graph:] All printable characters, not including space
[:print:] All printable characters, including space
https://github.com/ITEC4B/ASCII-random-string-generator