Hi,
I need a script to read the n° character from a text file.
eg: if the text file contains the line "123456" ,I nedd a command to display the number 4, as an example.
I tried with awk and printf but it seems only works with words separated with spaces, but in this case I have only one word... (15 Replies)
I need a better way to read the first character of each line in a file and check if it equals the special character ¤. This character tells me where there is a break in the reports. The file has over 500,000 lines. Currently, this is my code -
if ]
I am using Korn Shell as a scripting... (7 Replies)
im having trouble doing this:
i have a variable with 2 characters repeating e.g. aababbbaaaababaabbaabbba
is there a way i can search the variable for a's and b's and then change a's to b's and b's to a's?
im guessing its like getting the 1's compliment of the string
im doing this in... (2 Replies)
i am a newbie to shell script,so i want a kshell script in which i need to check for a particular character inside a file through conditional looping(like if ,case,while)and if that character exists ,then substitute a given character to that character.
consider a file test.txt,inside the file... (1 Reply)
Can someone help me to write a script / command to read in a file, character by character, replace any unknown ASCII characters with space. then write out the file to a new filename/
Thanks! (1 Reply)
Hi All,
I have a big log file i want to delete all characters (between 350th to 450th characters) starting at 350th character position to 450th character position.
please advice or sample code. (6 Replies)
Hi,
How read character by character from a file .
and i need replace '.' with null if it comes as a 5 character
i am beginner ...please help me (1 Reply)
hello all
i request you to give the solution for the following problem..
I want read the text file.and print the contents character by character..like if the text file contains google means..i want to print
g
go
goo
goog
googl
google
like this Using unix Shell scripting...
without using... (1 Reply)
Hi friend,
I have one file , and i want to read that file character by character.
I need this script in ksh.
while using read option with -n1 am getting error.
while read -n1 c read has bad option
And if i am using below script, then if in a line has space like this ( Pallvi mahajan)... (10 Replies)
Discussion started by: pallvi_mahajan
10 Replies
LEARN ABOUT NETBSD
pcap_loop
PCAP_LOOP(3) Library Functions Manual PCAP_LOOP(3)NAME
pcap_loop, pcap_dispatch - process packets from a live capture or savefile
SYNOPSIS
#include <pcap/pcap.h>
typedef void (*pcap_handler)(u_char *user, const struct pcap_pkthdr *h,
const u_char *bytes);
int pcap_loop(pcap_t *p, int cnt,
pcap_handler callback, u_char *user);
int pcap_dispatch(pcap_t *p, int cnt,
pcap_handler callback, u_char *user);
DESCRIPTION
pcap_loop() processes packets from a live capture or ``savefile'' until cnt packets are processed, the end of the ``savefile'' is reached
when reading from a ``savefile'', pcap_breakloop() is called, or an error occurs. It does not return when live read timeouts occur. A
value of -1 or 0 for cnt is equivalent to infinity, so that packets are processed until another ending condition occurs.
pcap_dispatch() processes packets from a live capture or ``savefile'' until cnt packets are processed, the end of the current bufferful of
packets is reached when doing a live capture, the end of the ``savefile'' is reached when reading from a ``savefile'', pcap_breakloop() is
called, or an error occurs. Thus, when doing a live capture, cnt is the maximum number of packets to process before returning, but is not
a minimum number; when reading a live capture, only one bufferful of packets is read at a time, so fewer than cnt packets may be processed.
A value of -1 or 0 for cnt causes all the packets received in one buffer to be processed when reading a live capture, and causes all the
packets in the file to be processed when reading a ``savefile''.
(In older versions of libpcap, the behavior when cnt was 0 was undefined; different platforms and devices behaved differently, so code that
must work with older versions of libpcap should use -1, nor 0, as the value of cnt.)
callback specifies a pcap_handler routine to be called with three arguments: a u_char pointer which is passed in the user argument to
pcap_loop() or pcap_dispatch(), a const struct pcap_pkthdr pointer pointing to the packet time stamp and lengths, and a const u_char
pointer to the first caplen (as given in the struct pcap_pkthdr a pointer to which is passed to the callback routine) bytes of data from
the packet.
RETURN VALUE
pcap_loop() returns 0 if cnt is exhausted, -1 if an error occurs, or -2 if the loop terminated due to a call to pcap_breakloop() before any
packets were processed. It does not return when live read timeouts occur; instead, it attempts to read more packets.
pcap_dispatch() returns the number of packets processed on success; this can be 0 if no packets were read from a live capture (if, for
example, they were discarded because they didn't pass the packet filter, or if, on platforms that support a read timeout that starts before
any packets arrive, the timeout expires before any packets arrive, or if the file descriptor for the capture device is in non-blocking mode
and no packets were available to be read) or if no more packets are available in a ``savefile.'' It returns -1 if an error occurs or -2 if
the loop terminated due to a call to pcap_breakloop() before any packets were processed. If your application uses pcap_breakloop(), make
sure that you explicitly check for -1 and -2, rather than just checking for a return value < 0.
If -1 is returned, pcap_geterr() or pcap_perror() may be called with p as an argument to fetch or display the error text.
SEE ALSO pcap(3), pcap_geterr(3), pcap_breakloop(3)
24 December 2008 PCAP_LOOP(3)