Shell Scripting
From COMP15212 Wiki
| Depends on | Shell |
|---|
Here is an example of Unix shell scripting with a view to showing how some other facilities can be exploited.
Examples
Example 1
#!/bin/bash
while read line1
do
read line2
echo "$line1 $line2"
done \
| while read a b c d
do
echo "$d $c $b $a"
done
This script runs two processes: the first reads two lines of input (the presence of the first controlling the while loop) and passes these, concatenated into a single line with a space separator, via a pipe to the other process. The second loop reads four temporary values into (environment) variables, then echoes these back
to the stdout stream in reverse order.
The simple way to use this script would be to redirect the standard streams to files, thus: script <input >output
An example input file is included in here and is duplicated below for reference.
1z 1y
1x 1w
2z 2y
2x 2w
3z 3y
3x 3w
4z 4y
4x 4w
5z 5y
5x 5w
6z 6y
6x 6w
7z 7y
7x 7w
8z 8y
8x 8w
9z 9y
9x 9w
10z 10y
10x 10w
