The for loop should end with a simple done.
Indeed a for loop is made to cycle through a list in memory; if the list is made from a file then the whole file must fit into memory.
In contrast, a while-read loop reads a file line by line. Most efficient if you can read each field into a distinct variable.
Quoting a lone $var in an assignment is not needed.
Code:
OLDIFS=$IFS
IFS=$OLDIFS
But quoting is a must in command arguments
Code:
if [ -n "$var" ]; then echo "$var"; fi
Last edited by MadeInGermany; 12-04-2016 at 07:17 AM..
This User Gave Thanks to MadeInGermany For This Post:
I have a command nested in some while loops to parse some data that looks something like this.
while ($condition)
while ($condition)
...
gzcat /dir/$fileName.gz | grep $searchString > out_file
end
end
On the first loop, the command is executed properly (and takes maybe 10... (3 Replies)
i have a line like this in my script
IP=`get_IP <hostname> | awk '{ print $1 }'
echo $IP
the problem is get_IP <hostname> returns data formated as follows:
ip 1.1.1.1 name server_name
the code above returns
1.1.1.1 server_name and i just need the 1.1.1.1
I have tried to add "|... (5 Replies)
Hi I am using a awk command but not getting required o/p.
input file
a.txt
2 ak
3 cb
4 de
5 gh
6 ij
awk program
BEGIN { x=0 }
{if ($1>3) {x=x+1}{print $0} }
END { print "I found " x " line have value more than 3" }
output
2 ak
3 cb
4 de
5 gh
6 ij (3 Replies)
Hello,
Recently, I've started with shell scripting, and decided to write a script for my system backup using tar. When I was dealing with tar execution inside shell script I found this, inside shell we have the following code:
tar $TAR_PARAMS $ARCHIVE_FILE $EXCLUDE $BACKUP_STARTwith... (6 Replies)
Hey everyone
I have a file 'agenda' which contains:
Object Day Month Year
Birthday 09 02 2012
i want to extract from a script the line which contains the day the user typed.
for example if he type 09 the line is showed using... (4 Replies)
#!/bin/bash
#...
for i in `ls -c1 /usr/share/applications`
do
name="cat $i | grep ^Name= | cut -d = -f2"
echo $name
#...
done
Now inside name as output is present:
while i want only the result of the command.
Ideally i would like obtain that information using only bash ... or... (8 Replies)
Hello,
There is a process in AIX which is actually a oracle database user session but is running very slow When I use lsof it give below output
lsof /proc/21955180
In while loop:256
In while loop:256
In while loop:256
In while loop:256
Value of I :183 np:1024
Please... (1 Reply)
#!/bin/sh
# This script returns the number of rows updated from a function
echo "The execution is starting ....."
sqlplus -silent $UP <<EOF
set serveroutput on
set echo off
set pagesize 0
VAR no_rows_updated NUMBER;
EXEC :no_rows_updated :=0;
DECLARE
CURSOR c_update is
SELECT * FROM... (4 Replies)
Hello,
I am running below command as root user
#nodetool cfstats tests | grep "Memtable switch count"
Memtable switch count: 12
Where as when I try to run same command as another user it gives different result.
#su -l zabbix -s /bin/bash -c "nodetool cfstats tests | grep "Memtable switch... (10 Replies)
Discussion started by: Pushpraj
10 Replies
LEARN ABOUT DEBIAN
io::async::timer::absolute
IO::Async::Timer::Absolute(3pm) User Contributed Perl Documentation IO::Async::Timer::Absolute(3pm)NAME
"IO::Async::Timer::Absolute" - event callback at a fixed future time
SYNOPSIS
use IO::Async::Timer::Absolute;
use POSIX qw( mktime );
use IO::Async::Loop;
my $loop = IO::Async::Loop->new;
my @time = gmtime;
my $timer = IO::Async::Timer::Absolute->new(
time => mktime( 0, 0, 0, $time[4]+1, $time[5], $time[6] ),
on_expire => sub {
print "It's midnight
";
$loop->stop;
},
);
$loop->add( $timer );
$loop->run;
DESCRIPTION
This subclass of IO::Async::Timer implements one-shot events at a fixed time in the future. The object waits for a given timestamp, and
invokes its callback at that point in the future.
For a "Timer" object that waits for a delay relative to the time it is started, see instead IO::Async::Timer::Countdown.
EVENTS
The following events are invoked, either using subclass methods or CODE references in parameters:
on_expire
Invoked when the timer expires.
PARAMETERS
The following named parameters may be passed to "new" or "configure":
on_expire => CODE
CODE reference for the "on_expire" event.
time => NUM
The epoch time at which the timer will expire.
Once constructed, the timer object will need to be added to the "Loop" before it will work.
Unlike other timers, it does not make sense to "start" this object, because its expiry time is absolute, and not relative to the time it is
started.
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.14.2 2012-10-24 IO::Async::Timer::Absolute(3pm)