9302a1:~ osada$ cd unix_literacy
9302a1:unix_literacy osada$ mkdir exerdir
9302a1:unix_literacy osada$ cd exerdir
9302a1:exerdir osada$ pwd
/Users/osada/unix_literacy/exerdir
9302a1:exerdir osada$ ls -a
. ..
9302a1:exerdir osada$ echo "This is an exercise." > exer.txt
9302a1:exerdir osada$ cp exer.txt exer1.txt
9302a1:exerdir osada$ ls -l
total 2
-rw-r--r-- 1 osada cis 21 11 11 14:35 exer.txt
-rw-r--r-- 1 osada cis 21 11 11 14:36 exer1.txt
9302a1:exerdir osada$ cat exer.txt exer1.txt
This is an exercise.
This is an exercise.
9302a1:exerdir osada$ ls -al
total 4
drwxr-xr-x 2 osada cis 53 11 11 14:36 .
drwxr-xr-x 3 osada cis 383 11 11 14:33 ..
-rw-r--r-- 1 osada cis 21 11 11 14:35 exer.txt
-rw-r--r-- 1 osada cis 21 11 11 14:36 exer1.txt