Whenever you replace something in a text file you either have to memory map the whole in C, make changes, then close the file. Or. Loop through the original file processing line by line and write the new file. In Linux
will do this - update in place. (It does the loop behind closed curtains). Other UNIXES, no.
We need:
Your shell and your unix OS to go further.
And it would be nice to know why loops are out of the question. Sounds misguided to me.
I get a text file with 70+ columns (seperated by Tab) and about 10000 rows. The 58th Column is all numbers. But sometimes 58th columns has "/xxx=##" after the numeric data. I want to truncate this string using the script. Any Ideas...:confused: (3 Replies)
Hi all,
I have a script that scan files, find old templet and replace it with new one.
#!/bin/ksh
file_name=$1
old_templet=$2
new_templet=$3
# Loop through every file like this
for file in file_name
do
cat $file | sed "s/old_templet/new_templet/g" > $file.new
#do a global searce and... (8 Replies)
Looking for a way using sed/awk/perl to replace port numbers in a file with an incrementing number. The original file looks like...
Host cmg-iqdrw3p4
LocalForward *:9043 localhost:9043
Host cmg-iqdro3p3a
LocalForward *:10000 localhost:10000
Host cmg-iqdro3p3b
LocalForward... (2 Replies)
find . -type f -name "*.sql" -print|xargs perl -i -pe 's/pattern/replaced/g'
this is simple logic to find and replace in multiple files & folders
Hope this helps.
Thanks
Zaheer (0 Replies)
Hi,
I need an elegant solotion in php. I need to compare 2 arrays (array1 & array2), to find all instances of array 2 which is not in array1.
I don't want to see any instances of array1 wich is not in array2 (here "the")
Array1: This, is, the, data, of, array1
Array2: this, is, data, Of,... (2 Replies)
Hi,
I have a string of letters that are upper and lower case. I would like to replace all the lowercase letters with N. Also, there are only 4 letters, so it may be easier to replace each lower case letter with N. Either way, I do not know know to do this.
Example line
... (6 Replies)
Hi All,
I have a unix shell script file as below.
My task is
a)to replace 248 to 350 and need to create a new file as BW3_350.sh
b)to replace 248 to 380 and need to create a new file as BW3_380.sh
c)to replace 248 to 320 and need to create a new file as BW3_320.sh
there is no... (6 Replies)
I am making an eBook.
I am editing the html in BBedit.
I need to replace all <p class="s5"> with just a <p>.
How do I write this for GREP?
Thank you,
Abby (5 Replies)
Hi
I am looking to rename the contents of this dir, each one with a new timestamp, interval of a second for each so it the existing format is on lhs and what I want is to rename each of these to what is on rhs..hopefully it nake sense
CDR.20060505.150006.gb CDR.20121211.191500.gb... (3 Replies)
Discussion started by: rob171171
3 Replies
LEARN ABOUT DEBIAN
io::async::loop::epoll
IO::Async::Loop::Epoll(3pm) User Contributed Perl Documentation IO::Async::Loop::Epoll(3pm)NAME
IO::Async::Loop::Epoll - use "IO::Async" with "epoll" on Linux
SYNOPSIS
use IO::Async::Loop::Epoll;
use IO::Async::Stream;
use IO::Async::Signal;
my $loop = IO::Async::Loop::Epoll->new();
$loop->add( IO::Async::Stream->new(
read_handle => *STDIN,
on_read => sub {
my ( $self, $buffref ) = @_;
while( $$buffref =~ s/^(.*)
?
// ) {
print "You said: $1
";
}
},
) );
$loop->add( IO::Async::Signal->new(
name => 'INT',
on_receipt => sub {
print "SIGINT, will now quit
";
$loop->loop_stop;
},
) );
$loop->loop_forever();
DESCRIPTION
This subclass of IO::Async::Loop uses IO::Epoll to perform read-ready and write-ready tests so that the O(1) high-performance multiplexing
of Linux's epoll_pwait(2) syscall can be used.
The "epoll" Linux subsystem uses a registration system similar to the higher level IO::Poll object wrapper, meaning that better performance
can be achieved in programs using a large number of filehandles. Each epoll_pwait(2) syscall only has an overhead proportional to the
number of ready filehandles, rather than the total number being watched. For more detail, see the epoll(7) manpage.
This class uses the epoll_pwait(2) system call, which atomically switches the process's signal mask, performs a wait exactly as
epoll_wait(2) would, then switches it back. This allows a process to block the signals it cares about, but switch in an empty signal mask
during the poll, allowing it to handle file IO and signals concurrently.
CONSTRUCTOR
$loop = IO::Async::Loop::Epoll->new()
This function returns a new instance of a "IO::Async::Loop::Epoll" object.
METHODS
As this is a subclass of IO::Async::Loop, all of its methods are inherited. Expect where noted below, all of the class's methods behave
identically to "IO::Async::Loop".
$count = $loop->loop_once( $timeout )
This method calls the "poll()" method on the stored "IO::Epoll" object, passing in the value of $timeout, and processes the results of that
call. It returns the total number of "IO::Async::Notifier" callbacks invoked, or "undef" if the underlying "epoll_pwait()" method returned
an error. If the "epoll_pwait()" was interrupted by a signal, then 0 is returned instead.
SEE ALSO
o IO::Epoll - Scalable IO Multiplexing for Linux 2.5.44 and higher
o IO::Async::Loop::Poll - use IO::Async with poll(2)AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.14.2 2012-04-10 IO::Async::Loop::Epoll(3pm)