Sponsored Content
Full Discussion: Overwrite file every day
Top Forums Shell Programming and Scripting Overwrite file every day Post 302873837 by RudiC on Wednesday 13th of November 2013 09:13:50 AM
Old 11-13-2013
What if the file is held open by an application running? Will that application write to file offset 0, or will the file continue to exist on disk, but lose its directory entry?
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

How to compare prev day file to current day file

Hi all: I am new to this board and UNIX programming so please forgive if I don't explain something correctly. I am trying to write a script to keep track of our links, we link one program written for Client A to Client B's directory. What we want to do is to keep track of our linked programs... (1 Reply)
Discussion started by: Smurtzy
1 Replies

2. Shell Programming and Scripting

overwrite specific lines in a file

Hi all, I am trying to overwrite some lines of a very big file. I know the number of the line but I don't know how to point the cursor on its beginning. there is an option to notice the offset in lines? thanks! (7 Replies)
Discussion started by: csecnarf
7 Replies

3. UNIX Desktop Questions & Answers

shell overwrite lines in a file

Hello, I have an external file (file.txt). This shall be a kind of a config file for my shell script. I get the line numbers as to a corresponding entry by grep. Now I would like to substitute the corresponding line from the shell script back to the file and exactly on the same line number. ... (4 Replies)
Discussion started by: ACTGADE
4 Replies

4. UNIX for Dummies Questions & Answers

Restrict file overwrite through FTP

How can I restrict a user from overwriting a file once he has uploaded it through FTP. He can view the file but can't delete or overwrite it. (OS is UNIX, there is no restriction on client FTP software) Will be very glad if someone could resolve this problem. Thanks Imran Aziz Khan ... (7 Replies)
Discussion started by: imranak7
7 Replies

5. UNIX for Dummies Questions & Answers

Output to file but append rather than overwrite?

I am running a command which has a parameter that outputs the results to a file each time it is run. Here is the command: --fullresult=true > importlog.xml Can I add the output to the file rather than creating a new one which overwrites the existing one? If not can I make the file name... (2 Replies)
Discussion started by: Sepia
2 Replies

6. Shell Programming and Scripting

Unable to overwrite but can delete file

I'm debugging a ksh script written by someone else that does the following: It runs a command and redirects stdout to a file called dberror that already exists using ">". This command fails with the following error: The file access permissions do not allow the specified action. dberror:... (1 Reply)
Discussion started by: savage66
1 Replies

7. UNIX for Dummies Questions & Answers

overwrite file in multiple folders

I need to update the contents of a file that exists in several hundred folders. I'm on a mac. Can I use Terminal to execute a linux/unix command that will accomplish the overwriting of the file? (2 Replies)
Discussion started by: webguy262
2 Replies

8. Shell Programming and Scripting

Shell script to overwrite a file

Hi Guys, My requirement as follows, i want to write a shell script to display the files of a folder, i export it to a file to mail the file. The problem is the exported file is getting appended every time I run the script. I just want the file to be over written. can anyone suggest?? ... (4 Replies)
Discussion started by: Karthick N
4 Replies

9. Shell Programming and Scripting

Wget download file ( do not overwrite )

Hello all, I want to write auto update script for my embedded device, which can check and download newer version of my program and extract the files on the device. The download center is hosted on remote web server . Script checks the hosted file on web site and if the new version is there... (8 Replies)
Discussion started by: stefki
8 Replies

10. Shell Programming and Scripting

How to Undo overwrite file in UNIX?

Hi, Could anyone please advise if its possible in unix to undo the changes for a file that has been overwrriten. By mistake i have overwritten a file and now i need the original file, is there a way? Please Help!!! (2 Replies)
Discussion started by: mail.chiranjit
2 Replies
posix_fadvise(3C)					   Standard C Library Functions 					 posix_fadvise(3C)

NAME
posix_fadvise - file advisory information SYNOPSIS
#include <fcntl.h> int posix_fadvise(int fd, off_t offset, off_t len, int advice); DESCRIPTION
The posix_fadvise() function advises the system on the expected behavior of the application with respect to the data in the file associated with the open file descriptor, fd, starting at offset and continuing for len bytes. The specified range need not currently exist in the file. If len is zero, all data following offset is specified. The system may use this information to optimize handling of the specified data. The posix_fadvise() function has no effect on the semantics of other operations on the specified data, although it may affect the performance of other operations. The advice to be applied to the data is specified by the advice parameter and may be one of the following values: POSIX_FADV_NORMAL Specifies that the application has no advice to give on its behavior with respect to the specified data. It is the default characteristic if no advice is given for an open file. POSIX_FADV_SEQUENTIAL Specifies that the application expects to access the specified data sequentially from lower offsets to higher off- sets. POSIX_FADV_RANDOM Specifies that the application expects to access the specified data in a random order. POSIX_FADV_WILLNEED Specifies that the application expects to access the specified data in the near future. POSIX_FADV_DONTNEED Specifies that the application expects that it will not access the specified data in the near future. POSIX_FADV_NOREUSE Specifies that the application expects to access the specified data once and then not reuse it thereafter. These values are defined in <fcntl.h> RETURN VALUES
Upon successful completion, posix_fadvise() returns zero. Otherwise, an error number is returned to indicate the error. ERRORS
The posix_fadvise() function will fail if: EBADF The fd argument is not a valid file descriptor. EINVAL The value of advice is invalid, or the value of len is less than zero. ESPIPE The fd argument is associated with a pipe or FIFO. USAGE
The posix_fadvise() function has a transitional interface for 64-bit file offsets. See lf64(5). ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Committed | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ |Standard |See standards(5). | +-----------------------------+-----------------------------+ SEE ALSO
posix_madvise(3C), attributes(5), standards(5) SunOS 5.11 14 Jul 2008 posix_fadvise(3C)
All times are GMT -4. The time now is 06:17 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy