Reference no: EM13764349

1. Use vim (Lab Manual, page 34) to create a file named short with the follow¬ing line in it: echo 'hi there'

2. Use cat to verify the contents of short and then try to execute it. Use Is -1 to display the permissions for short. Read the tip on page 338 of Sobell.

3. Use chmod (pages 193 and 337 of Sobell) to make the file executable, dis¬play the permissions for short, and try executing the file again.

4. Add a line that starts with 11! (Sobell, page 338) to the beginning of short to make sure it is executed by bash.

5. Add a comment line (Sobell, page 340) to short that explains what the script does.

6. Within a shell script, the shell expands Si (a positional parameter; Sobel!, page 1023) to the first argument on the command line the script was called with. Write and execute a script named first that displays (sends to standard output) the first argument on the command line it was called with. Include the #! line and a comment. Remember to make the file executable.

7. The date (Sobell, page 218) utility displays the date and time. Write and exe¬cute a shell script named mine that displays the date and time, the name of your home directory, and the value of your PATH variable.

8. Write a shell script that copies the file named by its first argument to a file with the same name with the filename extension of .bak. Thus, if you call the script with the argument first (and a file named first exists in the work-ing directory), after the script runs you would have two files: first and first.bak. Demonstrate that the script works properly.

9. Read the caution titled "Always quote positional parameters" on page 1023 of Sobell. Use touch to create a file whose name has a SPACE in it. What happens when you give that filename as an argument to cptobak from the previous step?

10. Modify the cptobak script from the previous step by quoting the positional parameters in the cp line. Now what happens when you use the script to make a copy of a file with a SPACE in its name?