construct:
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while expression
do
statements
done
In tcsh, use the following format:
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while (expression)
statements
End
If you want to add the first five even numbers, you can use the following shell
program in pdksh and bash:
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#!/bin/bash
loopcount=0
result=0
while [ $loopcount -lt 5 ]
do
loopcount=expr $loopcount + 1
increment=expr $loopcount \* 2
result=expr $result + $increment
doneecho "result is $result"
In tcsh, you can write this program as follows:
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#!/bin/tcsh
set loopcount = 0
set result = 0
while ($loopcount < 5)
set loopcount = expr $loopcount + 1
set increment = expr $loopcount \* 2
set result = expr $result + $increment
end
echo "result is $result"The until Statement
You can use the until statement to execute a series of commands until a
specified condition is true.
The loop terminates as soon as the specified condition evaluates to true.