UNIX Command Practice

Writing a Shell Script A shell script is just a file with a sequence of UNIX commands in it. Use a .sh extension for these to get proper syntax coloring. Here is an example. The echo command just spits what is handed it to stdout. Create this file.

echo Hello, World!

Now make the file executable and it will run your UNIX command. Do that as follows.

$ chmod +x hello.sh
$ ./hello.sh
Hello, World!

The first line is called the shebang line. It basically says, "this is a shell script." After it, just insert the UNIX commmands you want to have run. You can put shell scripts in your ~/bin directory and run them from anywhere in the file system.

Here is another example. It gives you date, time and a calender. It shows the environment variables LOGNAME and HOSTNAME being accessed.

echo Hello, $LOGNAME!
echo You are logged into the host $HOSTNAME
echo The current date and time are 
echo Here is a calendar for this month
$ ./time.sh
Hello, morrison!
You are logged into the host fluorine.ncssm.edu
The current date and time are
Fri Feb 24 10:47:16 EST 2017
Here is a calendar for this month
    February 2017   
Su Mo Tu We Th Fr Sa
          1  2  3  4
 5  6  7  8  9 10 11
12 13 14 15 16 17 18
19 20 21 22 23 24 25
26 27 28

You are going to write a shell script that performs various manipulations with the file scrabble.txt which you can download in the navigation area.

There is also a skeleton file provided, practice.sh. All of the problems are present in the skeleton file.