Hi,
I have a file named "Test_2008_01_21"
The file contains a string "manual" that occurs many times in the file
How can i find the positions of the string "manual" in the file
Ex: if the string " manual " occurs three times in the file. i want to replace the second occurance of string... (6 Replies)
Hi All,
My requisite is to search for the string "0108"(which is the year and has come in the wrong year format) in a particular column say 4th column in a tab delimited file and then replace it with 2008(the correct year format) in the same position where 0108 was found..The issue is the last... (15 Replies)
Hi
I am looking for a particular string in a file.If the string exists, then I want to replace another string with some other text.Once replaced, search for the same text after that character position in the file. :wall:
E.g: Actual File content:
Hello
Name: Nitin Raj
Welcome to Unix... (4 Replies)
here is what i want to achieve... consider a file contains below contents. the file size is large about 60mb
cat dump.sql
INSERT INTO `table1` (`id`, `action`, `date`, `descrip`, `lastModified`) VALUES (1,'Change','2011-05-05 00:00:00','Account Updated','2012-02-10... (10 Replies)
I am having a text file which is having more than 200 lines.
EX:
001010122 12000 BIB 12000 11200 1200003
001010122 2000 AND 12000 11200 1200003
001010122 12000 KVB 12000 11200 1200003
In the above file i want to search for string KVB and add/replace... (1 Reply)
Need Assistance in shell programming... I have a huge file which has multiple stations and i wanted to search particular station and extract few lines from it and the rest is not needed
Bold letters are the stations . The whole file has multiple stations .
Below example i wanted to search... (4 Replies)
Hi,
I have a file with multiple lines(fixed width dat file). I want to search for '02' in the positions 45-46 and if available, in that lines, I need to replace value in position 359 with blank. As I am new to unix, I am not able to figure out how to do this. Can you please help me to achieve... (9 Replies)
Hi Everyone,
I have a requirement in ksh where i have a set of files in a directory. I need to search each and every file if a particular string is present in the file, delete that line and replace that line with another string expression in the same file.
I am very new to unix. Kindly help... (10 Replies)
I have the below string which i need to compare with a file and replace this string in the file which matches closely. Can anyone help me on this.
string(Scenario 1)- user::r--,user::ourfrd:r--
String(Scenario 2)- user::r--
File
****
# file: /local/Desktop/myfile
# owner: me
# group:... (6 Replies)
Discussion started by: sarathy_a35
6 Replies
LEARN ABOUT REDHAT
mprotect
MPROTECT(2) Linux Programmer's Manual MPROTECT(2)NAME
mprotect - control allowable accesses to a region of memory
SYNOPSIS
#include <sys/mman.h>
int mprotect(const void *addr, size_t len, int prot);
DESCRIPTION
mprotect controls how a section of memory may be accessed. If an access is disallowed by the protection given it, the program receives a
SIGSEGV.
prot is a bitwise-or of the following values:
PROT_NONE The memory cannot be accessed at all.
PROT_READ The memory can be read.
PROT_WRITE The memory can be written to.
PROT_EXEC The memory can contain executing code.
The new protection replaces any existing protection. For example, if the memory had previously been marked PROT_READ, and mprotect is then
called with prot PROT_WRITE, it will no longer be readable.
RETURN VALUE
On success, mprotect returns zero. On error, -1 is returned, and errno is set appropriately.
ERRORS
EINVAL addr is not a valid pointer, or not a multiple of PAGESIZE.
EFAULT The memory cannot be accessed.
EACCES The memory cannot be given the specified access. This can happen, for example, if you mmap(2) a file to which you have read-only
access, then ask mprotect to mark it PROT_WRITE.
ENOMEM Internal kernel structures could not be allocated.
EXAMPLE
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/mman.h>
#include <limits.h> /* for PAGESIZE */
#ifndef PAGESIZE
#define PAGESIZE 4096
#endif
int
main(void)
{
char *p;
char c;
/* Allocate a buffer; it will have the default
protection of PROT_READ|PROT_WRITE. */
p = malloc(1024+PAGESIZE-1);
if (!p) {
perror("Couldn't malloc(1024)");
exit(errno);
}
/* Align to a multiple of PAGESIZE, assumed to be a power of two */
p = (char *)(((int) p + PAGESIZE-1) & ~(PAGESIZE-1));
c = p[666]; /* Read; ok */
p[666] = 42; /* Write; ok */
/* Mark the buffer read-only. */
if (mprotect(p, 1024, PROT_READ)) {
perror("Couldn't mprotect");
exit(errno);
}
c = p[666]; /* Read; ok */
p[666] = 42; /* Write; program dies on SIGSEGV */
exit(0);
}
CONFORMING TO
SVr4, POSIX.1b (formerly POSIX.4). SVr4 defines an additional error code EAGAIN. The SVr4 error conditions don't map neatly onto Linux's.
POSIX.1b says that mprotect can be used only on regions of memory obtained from mmap(2).
SEE ALSO mmap(2)Linux 2.0 1997-05-31 MPROTECT(2)