05-02-2012
10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Hello UNIX experts,
I have 124 text files in a directory. I want to extract the 45678th line of all the files sequentialy by file names. The extracted lines should be printed in the output file on seperate lines.
e.g. The input Files are one.txt, two.txt, three.txt, four.txt
The cat of four... (1 Reply)
Discussion started by: yogeshkumkar
1 Replies
2. UNIX for Dummies Questions & Answers
does anyone have an awk one-liner to:
print the first line, the second line, then every Nth line, and the last line of a file.
Thanks,
Kenny. (5 Replies)
Discussion started by: kenneth.mcbride
5 Replies
3. Shell Programming and Scripting
Hi
I have requirement to find nth occurrence in a file and capture data from with in lines (between lines)
Data in File.
<QUOTE>
<SESSION>
<ATTRIBUTE NAME='Parameter Filename' VALUE='file1.parm'/>
<ATTRIBUTE NAME='Service Name' VALUE='None'/>
</SESSION>
<SESSION>
<ATTRIBUTE... (6 Replies)
Discussion started by: tmalik79
6 Replies
4. Shell Programming and Scripting
Hi,
For my reuirement, I have to read a file from the 2nd line till the last line<EOF>.
Say,
I have a file as test.txt, which as a header record in the first line followed by records in rest of the lines.
for i in `cat test.txt`
{
echo $i
}
While doing the above loop, I have read... (5 Replies)
Discussion started by: machomaddy
5 Replies
5. Shell Programming and Scripting
Is there an awk script that can easily perform the following operation?
I have a data file that is in the format of
1944-12,5.6
1945-01,9.8
1945-02,6.7
1945-03,9.3
1945-04,5.9
1945-05,0.7
1945-06,0.0
1945-07,0.0
1945-08,0.0
1945-09,0.0
1945-10,0.2
1945-11,10.5
1945-12,22.3... (3 Replies)
Discussion started by: ncwxpanther
3 Replies
6. UNIX for Dummies Questions & Answers
Hey,
I'm sure this is answered somewhere but my Googling has turned up nothing. I have a file with data in the following format:
<desription of event> at <time and date>The desription of the event is variable length and hence when the list is displayed it is hard to easily see the date (and... (8 Replies)
Discussion started by: RECrerar
8 Replies
7. Shell Programming and Scripting
Bash/Oracle Linux 6.4
A basic requirement.
How can I get nth line of a file printed ? Can I use grep in this case ?
Example:
In the below file, 12th line is "Kernel parameter check passed for rmem_max" . I just want the 12 line to be printed.
# cat sometext.txt
Kernel version check... (2 Replies)
Discussion started by: John K
2 Replies
8. UNIX for Beginners Questions & Answers
Hi All,
I am using UNix Sun OS sun4u sparc SUNW,SPARC-Enterprise
My intention is to insert a line of text after 13th line of every file inside a particular directory.
While trying to do it for a single file , i am using sed
sed '3 i this is the 4th line' filename
sed: command garbled: 3... (5 Replies)
Discussion started by: gotamp
5 Replies
9. AIX
Please help me
print nth line after match
awk or sed one line command. (3 Replies)
Discussion started by: sushma123
3 Replies
10. Shell Programming and Scripting
My file (the output of an experiment) starts off looking like this,
_____________________________________________________________
Subjects incorporated to date: 001
Data file started on machine PKSHS260-05CP
**********************************************************************
Subject 1,... (9 Replies)
Discussion started by: samonl
9 Replies
LEARN ABOUT FREEBSD
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 in:
FreeBSD prior to FreeBSD 4.6;
NetBSD prior to NetBSD 3.0;
OpenBSD prior to OpenBSD 2.4;
Mac OS X prior to Mac OS X 10.7;
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), but a simple select() or poll() will not indicate that the descriptor is readable until a full
buffer's worth of packets is received, even if the read timeout expires before then. 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() indicated 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; however, 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)
22 July 2011 PCAP_GET_SELECTABLE_FD(3)