Where command_t is executed and its exit status tested. If it's zero, the commands enclosed between the do and done are executed. Then command_t is executed again and its exit status tested. If it's zero, the commands enclosed between the do and done are once again executed. This process continues until command_t returns a nonzero exit status. At that point, execution of the loop is terminated. Execution then proceeds with the command that follows the done.
Why not substitute 1 with true and drop the parenthesis, braces, and brackets
Hi,
please can someone point me in the right direction with a shell scripting problem.
I want to execute a command in a for loop and the command should be started not one-by-one meaning the for loop is waiting for the exit code , it should be started in parallel.
I have a plain text file... (3 Replies)
I have a very basic bash shell script, which has many "while... done; for .... done" loop clauses, like the following
~~
#!/bin/bash
while blablalba; do
....
done < /tmp/file
for line in `cat blablabla`; do grep $line /tmp/raw ; done > /tmp/1;
while blablalba2; do
....
done <... (2 Replies)
I want to execute a while loop (or any other loop) for 20 minutes.
I have extracted the minutes and seconds from the current system date by using the command y = `date +%M%S`
How to proceed ?? (6 Replies)
Hello,
I have a set of input data that I split into batches using the following command:
split -l 4000000 MyInput.in Split_a
Once I get the split files, I run a certain command on the split files that spews an output. So far I have been doing it without a for loop. How can I translate the... (2 Replies)
Hi everyone.
I wanted to print numbers from 1 to 5 in reverse order. For this I used the following code:
#!/bin/bash
x=5
while
do
echo $x
x=`expr $x - 1`
echo ""
done
echo ""
Well but on compiling the above code, it gives the following error.
... (3 Replies)
HI Unix Gurus,
I have a number of SELECT count(*) statements in an input file and I want to execute it using a shell script but one by one using loop in script....
How can I do this..... (7 Replies)
I have a below command
ALTER TABLE `abc` ADD PARTITION ( PARTITION 20130613 VALUES less than (DAY('13')));
Below is requirement
It runs in Loop
as DAY start with 13 and end with 100 along with this of counter "20130613" also increases per command
as the next command should be
... (8 Replies)
Hi,
I have first script which on IR remote command event execute the second script. If the second script is executed, it display echo "timeout expired" after 10s. This works as expected.
But I also want to reset timer (increase time) in case if the second script is executed again within 10s.
... (8 Replies)
Discussion started by: armatron
8 Replies
LEARN ABOUT REDHAT
while
while(n) Tcl Built-In Commands while(n)
__________________________________________________________________________________________________________________________________________________NAME
while - Execute script repeatedly as long as a condition is met
SYNOPSIS
while test body
_________________________________________________________________DESCRIPTION
The while command evaluates test as an expression (in the same way that expr evaluates its argument). The value of the expression must a
proper boolean value; if it is a true value then body is executed by passing it to the Tcl interpreter. Once body has been executed then
test is evaluated again, and the process repeats until eventually test evaluates to a false boolean value. Continue commands may be exe-
cuted inside body to terminate the current iteration of the loop, and break commands may be executed inside body to cause immediate termi-
nation of the while command. The while command always returns an empty string.
Note: test should almost always be enclosed in braces. If not, variable substitutions will be made before the while command starts execut-
ing, which means that variable changes made by the loop body will not be considered in the expression. This is likely to result in an
infinite loop. If test is enclosed in braces, variable substitutions are delayed until the expression is evaluated (before each loop iter-
ation), so changes in the variables will be visible. For an example, try the following script with and without the braces around $x<10:
set x 0
while {$x<10} {
puts "x is $x"
incr x
}
SEE ALSO
break(n), continue(n), for(n), foreach(n)
KEYWORDS
boolean value, loop, test, while
Tcl while(n)
01-20-2009
