04-27-2009
devtak the code doent seem to work.it always prints "does not exists"
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1. Shell Programming and Scripting
Hi,
I'd like to grep a variable that I saved in the program.
Like
grep '0\$variable1' file1
Does someone know what's wrong with this command?
Thanks a lot! (2 Replies)
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2. Shell Programming and Scripting
Hi, I can't get this script to work (returns 0, should return 3):
$ cat A.lst | \
while read LINE
do
echo "$LINE"
grep -c "$LINE" B.tmp
done> > > > >
Socket
0
$
but in contrast this one works fine (returns 3 as expected):
$ LINE=Socket
$ grep -c $LINE B.tmp
3
$ (5 Replies)
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Hi all,
I am trying to do a simple thing in my mind. However I am fairly new to bash. What I need to do is create a folder for each partition on each CD, and each partition has a unique name (with spaces in it, do not ask why, it is already done :confused: ) . All CD's will show up... (2 Replies)
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4. Shell Programming and Scripting
how can I use grep with a variable to find a value?
cat data.out
Hello World
grep "Hello World" data.out
Hello World ## Value found
I want to do something like this but can't seem to get it to work any
suggestions would be appreciated.
var="Hello World"
grep $var data.out (3 Replies)
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5. Shell Programming and Scripting
I want to search a text in file but that file is pointing to variable.
ex:
file=there was nothing special
grep "there was nothing" $file
but its not working . Can u let me know that how we can use variable($file) in grep command.
Please use code tags (6 Replies)
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6 Replies
6. Shell Programming and Scripting
I have a pattern like:
column "5" is missing
PS: the no is in double quotes.
The number usally changes, so we use a loop to grep.
grep 'column "$number" is missing' filename.txt
But it is not working....
How to solve this? (2 Replies)
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7. Shell Programming and Scripting
Hello,
I usually search extensively and have to date found what I've needed. However, this one's got me stumped. I need to create a variable as follow. The issue however is that upon execution, it freezes. $var1 isn't always present in usage.log and this is fine but I'd like it to continue with... (6 Replies)
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I've got a file that I'm trying to grep through that looks like this:
alpha1
alpha2
alpha3
beta1
beta2
gamma5
gamma6
gamma7
gamma8
gamma9
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alpha3
beta2
gamma9
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9. Shell Programming and Scripting
Hi,
I am trying to grep one variable over the other variable
Example:
i=abc
j=ab
grep $j $i
I am getting this error:
The error is due to $i being variable and not file. I know I could do it by putting the value of abc in a file
and then greping it. (1 Reply)
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10. UNIX for Beginners Questions & Answers
hi
i have a file which contains some messages counters.
below is the snippet on the file.
17-05-29::22:36:21|message|231
17-05-29::22:36:31|message|222
17-05-29::22:36:41|message|213
17-05-30::22:36:51|message|221
17-05-30::22:37:01|message|227
17-05-30::22:37:11|message|207... (5 Replies)
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LEARN ABOUT NETBSD
pcap_get_selectable_fd
PCAP_GET_SELECTABLE_FD(3) Library Functions Manual PCAP_GET_SELECTABLE_FD(3)
NAME
pcap_get_selectable_fd - get a file descriptor on which a select() can be done for a live capture
SYNOPSIS
#include <pcap/pcap.h>
int pcap_get_selectable_fd(pcap_t *p);
DESCRIPTION
pcap_get_selectable_fd() returns, on UNIX, a file descriptor number for a file descriptor on which one can do a select() or poll() to wait
for it to be possible to read packets without blocking, if such a descriptor exists, or -1, if no such descriptor exists. Some network
devices opened with pcap_create() and pcap_activate(), or with pcap_open_live(), do not support select() or poll() (for example, regular
network devices on FreeBSD 4.3 and 4.4, and Endace DAG devices), so -1 is returned for those devices.
Note that on most versions of most BSDs (including Mac OS X) select() and poll() do not work correctly on BPF devices;
pcap_get_selectable_fd() will return a file descriptor on most of those versions (the exceptions being FreeBSD 4.3 and 4.4), a simple
select() or poll() will not return even after the read timeout expires. To work around this, an application that uses select() or poll()
to wait for packets to arrive must put the pcap_t in non-blocking mode, and must arrange that the select() or poll() have a timeout less
than or equal to the read timeout, and must try to read packets after that timeout expires, regardless of whether select() or poll() indi-
cated that the file descriptor for the pcap_t is ready to be read or not. (That workaround will not work in FreeBSD 4.3 and later; how-
ever, in FreeBSD 4.6 and later, select() and poll() work correctly on BPF devices, so the workaround isn't necessary, although it does no
harm.)
Note also that poll() doesn't work on character special files, including BPF devices, in Mac OS X 10.4 and 10.5, so, while select() can be
used on the descriptor returned by pcap_get_selectable_fd(), poll() cannot be used on it those versions of Mac OS X. Kqueues also don't
work on that descriptor. poll(), but not kqueues, work on that descriptor in Mac OS X releases prior to 10.4; poll() and kqueues work on
that descriptor in Mac OS X 10.6 and later.
pcap_get_selectable_fd() is not available on Windows.
RETURN VALUE
A selectable file descriptor is returned if one exists; otherwise, -1 is returned.
SEE ALSO
pcap(3), select(2), poll(2)
5 April 2008 PCAP_GET_SELECTABLE_FD(3)