When you put a code block behind a pipe, the entire block executes in a subshell. The subshell inherits a copy of the shell's current variables but cannot communicate them back(much like how processes inherit environment variables). So the loop runs fine but the number you want was never in the parent shell.
You could either accomplish the loop without a pipe (perhaps by saving the output of ps to a temporary file), or have the loop output values to stdout to be read further down the pipe chain.
P.S.: You could replace
with
There seems to be no point to saving it to a temp file when all you want it to do is print to the console anyway.
Last edited by Corona688; 02-11-2010 at 04:29 PM..
I have,
LIST="a b c d e"
for word in $LIST
do
echo $word
done
would give me
a
b
c
d
e
With the first iteration of the for loop, I get "a" as the result.
Is it possible that I get both "a" and "b" in only the first iteration.
In the next iteration I get "c" and "d" and so on.... (2 Replies)
Another question, is it possible to, in a for-loop incrementing until it reaches a certain number, to have it loop again without incrementing? Just have it drop what it is doing when it reaches this command and start again at the same number it was at? I know I could make a while loop and just... (0 Replies)
I need to execute a KornShell (SunOS 5.9) script against a range of dates:
endDate=20080804
extractDate=20080401
while ; do
batch < scripts/myshellscript.sh $extractDate
## add 1 day to extractDate ##
done
My question is how do I increment the extractDate variable and still have it... (3 Replies)
Hi all,
I have a variable with date as 20080831 . Now I want to increment it as 20080901 and so on.Is there any command for this. Please help me.
thanks
rameez (1 Reply)
Hi All,
Iam trying to increment a variable
Following is the code
#!/usr/bin/ksh
i=1;
i='expr $i+1';
echo $i;
Output:
expr $i+1
not able to understand why its happening in that way
i was expecting result as 2... if the above method is worng .. can you help how i can get... (3 Replies)
Hi,
I am using BASH. I have encountered a situation where the following is necessary (but I am not sure how to do it):
#Define multiple arrays, whose names only differ by a number:
ARRAY_1=(1 2 3)
ARRAY_2=(4 5 6)
ARRAY_3=(7 8 9)
#Define ARRAY_AMOUNT, the number of arrays. In this case... (1 Reply)
Hi,
want to increment a variable in a for loop like this:
for (( c=$total-1; c>=0; c-- ))
do
if ;
then
maximo=$valores
fi
done
But it gives the error:
No such file or directory
How can i do this only incrementing the c variable?
Thanks (8 Replies)
Hello folks.
I am trying to increment my variable names to match a counter that is to be used later on...
Basically, i have a for loop that lists directories (for example TEST_OS DVP_OS PROD_OS ) but this loop is not static, it may contain 3 directory once and the next run 5 directories.
I... (6 Replies)
Hi!
Can anyone explain this? The counter CDR_count should go on forever, but it suddenly resets at every step of the FOR loop (I know this because $_file has exactly 378 records). However, the counter reset is OUTSIDE the FOR loop. What's going on??
#!/bin/bash
if || ; then
echo
... (8 Replies)
Discussion started by: Flavius
8 Replies
LEARN ABOUT CENTOS
tping
TPING(1) LAM COMMANDS TPING(1)NAME
tping - Send echo messages to LAM nodes.
SYNOPSIS
tping [-hv] [-c count] [-d delay] [-l length] nodes
OPTIONS -h Print the command help menu.
-v Turn OFF verbose mode.
-c count Send count messages.
-d delay Delay delay seconds between each message.
-l length Each message is length bytes long.
DESCRIPTION
The tping command sends messages to, and collects replies from, a list of nodes, via the LAM echo server. It is similar to the UNIX
ping(8) command, and is used as a quick diagnosis of the LAM network.
Unless options are specified, tping sends a 1 byte message an infinite number of times, displaying the roundtrip time of each message as it
completes, with a delay of 1 second between roundtrips. After the loop is broken (with keyboard interrupt, eg: ^C), tping prints statis-
tics about all roundtrip messages.
EXAMPLES
tping h
Echo messages to the local node.
tping -v n7 -l 1000 -c 10
Echo 1000 byte messages to node 7. Stay silent while working. Stop after 10 roundtrips and report statistics.
BUGS
There is no built-in timeout and tping will wait forever to receive an echo. If no echo is received, due to a dead link or node, tping
hangs. Stop the process with a keyboard suspend signal (eg: ^Z) and terminate LAM with lamhalt(1) or lamwipe(1) (although the use of
lamwipe(1) is deprecated).
SEE ALSO lamhalt(1), lamwipe(1)LAM 7.1.4 July, 2007 TPING(1)