I was just looking into this. What I've found is the following:
Code:
awk 'NR==FNR{a[$1];next}$1 in a{print $1}' F1 F2
NR==FNR -- this will only be true when in the first file
a[$1] use the first column to make array of file
next skip all the next blocks and process the next line
($1 in a) check in value in column on of second file
then print it
Code:
gawk 'FNR==NR {a[$1]++;next} ($2 in a) {print $2}'
So this is NR==FNR same as above
a[$1] s same as above
$2 in a -- is column $2 in the array of second file? then print it
Hello ,
I am trying to print the footer of evry file in the given directory with xargs command like follows
ls -1 | xargs -I {} gzcat {} | tail -1
now problem with this is only last file foooter is getting printed as " | tail -1 " is getting executed for the last file.
I know this can... (4 Replies)
Hi all,
I'm working with flex (version 2.5.4a) on GNU/linux. I used it to develop 4 scanner C files for matching different patterns within an input file. But the problem now on my hand is that I need to conditionally combine these. That is in main (placed in a separate C file other than the 4... (5 Replies)
I've got:
isql -U $USERID -S $SERVER -D $DATABASE -i inputfile.sql -o outputfile.txt
in inputfile I have:
go
sql#1
go
sql#2
go
sql#3
go
I also tried without "go" and with";" instead which did not work
SQL statements will work if I paste them directly into the script and use EOF
... (0 Replies)
Hi there,
I am trying to figure out a way to combine multiple sources with different data on a single file, and I am trying to find the best way to do it.
I have multiple files, let's say A, B, C and D. A has a field in common with B, B has a field in common with C, and C has a field in... (2 Replies)
Being new to this area .I have been assigned a task which i am unable to do . Can any one please help me .
Hi I have requirement where i have input file XYZ_111_999_YYYYMMDD_1.TXT and with header and series of Numbers and Footer.
I want to create a mutiple output files with each file having a... (2 Replies)
Hi,
I'm working on a script which has to copy multiple files from one server to another server. The list of files that are to be copied is present in a file say input.txt.
vi input.txt
abc.c
welcome.c
new.c
welcome1.c
for ftp'ing a single file say 'new.c' the following code... (2 Replies)
Hello,
I have been working on script in which search and replace the multiple pattern.
1. update_params.sh read the multiple pattern from input file ParamMapping.txt(old_entry|New_entry) and passing this values one by one to change_text.sh
2. change_text.sh read... (0 Replies)
GM,
I have an issue at work, which requires a simple solution. But, after multiple attempts, I have not been able to hit on the code needed.
I am assuming that sed, awk or even perl could do what I need.
I have an application that adds extra blank page feeds, for multiple reports, when... (7 Replies)
Discussion started by: jxfish2
7 Replies
LEARN ABOUT DEBIAN
io::async::pid
IO::Async::PID(3pm) User Contributed Perl Documentation IO::Async::PID(3pm)NAME
"IO::Async::PID" - event callback on exit of a child process
SYNOPSIS
use IO::Async::PID;
use POSIX qw( WEXITSTATUS );
use IO::Async::Loop;
my $loop = IO::Async::Loop->new;
my $kid = $loop->fork(
code => sub {
print "Child sleeping..
";
sleep 10;
print "Child exiting
";
return 20;
},
);
print "Child process $kid started
";
my $pid = IO::Async::PID->new(
pid => $kid,
on_exit => sub {
my ( $self, $exitcode ) = @_;
printf "Child process %d exited with status %d
",
$self->pid, WEXITSTATUS($exitcode);
},
);
$loop->add( $pid );
$loop->run;
DESCRIPTION
This subclass of IO::Async::Notifier invokes its callback when a process exits.
For most use cases, a IO::Async::Process object provides more control of setting up the process, connecting filehandles to it, sending data
to and receiving data from it.
EVENTS
The following events are invoked, either using subclass methods or CODE references in parameters:
on_exit $exitcode
Invoked when the watched process exits.
PARAMETERS
The following named parameters may be passed to "new" or "configure":
pid => INT
The process ID to watch. Must be given before the object has been added to the containing "IO::Async::Loop" object.
on_exit => CODE
CODE reference for the "on_exit" event.
Once the "on_exit" continuation has been invoked, the "IO::Async::PID" object is removed from the containing "IO::Async::Loop" object.
METHODS
$process_id = $pid->pid
Returns the underlying process ID
$pid->kill( $signal )
Sends a signal to the process
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.14.2 2012-10-24 IO::Async::PID(3pm)