Assignment 2: Shell Scripts
Complete assignment due: Thursday, Sept. 11th, 9 p.m.
Problem 1: Hidden Argument
Write a Korn shell script named hideArg.ksh that will print those command-line arguments that do not match the first command-line argument. After printing the non-hidden arguments, the script will print a count of the number of hidden arguments found among the 2nd and succeeding arguments.
Some examples:
$ ksh hideArg.ksh one two three one four one six
two
three
four
six
There were 2 hidden arguments
$ ksh hideArg.ksh one two "three one" "four one" six
two
three one
four one
six
There were no hidden arguments
$ ksh hideArg.ksh one two three one "four one" six
two
three
four one
six
There was 1 hidden argument
$ ksh hideArg.ksh
There were no hidden arguments
$
Turnin: Use the turnin program to turn in your completed hideArg.ksh script. The command is:
turnin 352assign2 hideArg.ksh
See the man page for the turnin program for details on what turnin can do and how you can confirm that your file was turned in.
Problem 2: One Pipe.
Write a Korn shell script named onePipe.ksh. The script will take each pair of command-line arguments and execute them using a pipe to connect the output of the first of the pair to the input of the second. For each pair of commands:
•Print the pair as a pipe.
•Show the result of executing the pair of commands
•State whether the first command produced output on standard error. If there is standard error output from the first command, print it.
•Print the exit status of the second command.
•After each pair of commands, print: a blank line, a row of 20 dashes, and a blank line.
If the number of command-line arguments is not divisible by 2, print an error message and a Usage statement and exit (see examples below). A script can send output to stderr by using >&2. For example:
echo "Text sent to stderr" >&2
will send the string to stderr.
If there are no command-line arguments, the script will simply exit.
Some examples:
$ ksh onePipe.ksh "cal 2008" wc
Executing: cal 2008 | wc
35 463 2019
cal 2008 produced nothing on standard error
Exit status of wc: 0
--------------------
$ ksh onePipe.ksh "cal -z 2008" wc
Executing: cal -z 2008 | wc
0 0 0
cal -z 2008 produced the following error output:
cal: invalid option -- 'z'
usage: cal [-13smjyV] [[month] year]
Exit status of wc: 0
--------------------
$ ksh onePipe.ksh "cal -3 2008" "wc -z"
Executing: cal -3 2008 | wc -z
wc: invalid option -- 'z'
Try `wc --help' for more information.
cal -3 2008 produced nothing on standard error
Exit status of wc -z: 1
--------------------
$ ksh onePipe.ksh "cat /home/cs352/fall08/books/gettysburg.txt" "wc" "ls -l /home/cs352/fall08/books/gettysburg.txt" "wc" "ls -l ~cs352/fall08/books" "fgrep 352"
Executing: cat /home/cs352/fall08/books/gettysburg.txt | wc
23 280 1495
cat /home/cs352/fall08/books/gettysburg.txt produced nothing on standard error
Exit status of wc: 0
--------------------
Executing: ls -l /home/cs352/fall08/books/gettysburg.txt | wc
1 8 92
ls -l /home/cs352/fall08/books/gettysburg.txt produced nothing on standard error
Exit status of wc: 0
--------------------
Executing: ls -l ~cs352/fall08/books | fgrep 352
ls -l ~cs352/fall08/books produced the following error output:
ls: cannot access ~cs352/fall08/books: No such file or directory
Exit status of fgrep 352: 1
--------------------
$ ksh onePipe.ksh "cal -3 10 2008"
Arguments must be paired
Usage: onePipe.ksh cmd1 cmd2 [cmd1 cmd2] ...
$ ksh onePipe.ksh
$ cp onePipe.ksh sample.ksh
$ sample.ksh "ls -z"
Arguments must be paired
Usage: sample.ksh cmd1 cmd2 [cmd1 cmd2] ...
$
Turnin: Use the turnin program to turn in your completed onePipe.ksh script. The command is:
turnin 352assign2 onePipe.ksh
See the man page for the turnin program for details on what turnin can do and how you can confirm that your file was turned in.
Final Summary:
There are two files that you will need to turnin for full credit on this assignment:
hideArg.ksh
onePipe.ksh