[cs50@flume ~/demo]$ echo hello > hello.c
[cs50@flume ~/demo]$ emacs hash.c
[cs50@flume ~/demo]$ ./backup-diff.sh 
hash.c differences:
2c2
<  * hash.c - will be a hash module
---
>  * hash.c - will be a hash module (someday!)
3a4,5
> 
> #include <stdio.h>

hello.c - no backup

queue.c unchanged

sort.c unchanged

[cs50@flume ~/demo]$ 
[cs50@flume ~/demo]$ 
(arg: -1) ^C
[cs50@flume ~/demo]$ ^C
[cs50@flume ~/demo]$ clear

[cs50@flume ~/demo]$ cp ~/examples/backup-diff-exit.sh .
[cs50@flume ~/demo]$ emacs backup-diff-exit.sh 
[cs50@flume ~/demo]$ ls
backup/		      backup.sh*  hash.c~     labs/    queue.c.bak  students.bak
backup-diff-exit.sh*  backup.sh~  hash.c.bak  LFlist   sort.c	    students.txt
backup-diff.sh*       hash.c	  hello.c     queue.c  sort.c.bak
[cs50@flume ~/demo]$ cp ~/examples/guessprime.sh
cp: missing destination file operand after '/net/class/cs50/examples/guessprime.sh'
Try 'cp --help' for more information.
[cs50@flume ~/demo]$ cp ~/examples/guessprime.sh .
[cs50@flume ~/demo]$ emacs guessprime.sh 
[cs50@flume ~/demo]$ ./guessprime.sh 
Enter a prime between 1-100: 2
Wrong! try again
Enter a prime between 1-100: 7
Wrong! try again
Enter a prime between 1-100: 64
Wrong! try again
Enter a prime between 1-100: 99999
Wrong! try again
Enter a prime between 1-100: ekrjhgdkfhdkf
Wrong! try again
Enter a prime between 1-100: whatever you type
./guessprime.sh: line 22: [: too many arguments
[cs50@flume ~/demo]$ emacs guessprime.sh 
[cs50@flume ~/demo]$ ./guessprime.sh 
Enter a prime between 1-100: whatever you type
Wrong! try again
Enter a prime between 1-100: 031
Wrong! try again
Enter a prime between 1-100: ^C
[cs50@flume ~/demo]$ fg
-bash: fg: current: no such job
[cs50@flume ~/demo]$ emacs guessprime.sh 
[cs50@flume ~/demo]$ ./guessprime.sh 
Enter a prime between 1-100: 031
[cs50@flume ~/demo]$ ./guessprime.sh 
Enter a prime between 1-100: whatever
./guessprime.sh: line 22: [: whatever: integer expression expected
[cs50@flume ~/demo]$