Unix flush file

You can employ it with the -s option that specifies the file size. To empty a file content, use a size of 0 zero as in the next command:. These are not probably the only available practical ways of doing this, so you can also tell us about any other methods not mentioned in this guide via the feedback section below. TecMint is the fastest growing and most trusted community site for any kind of Linux Articles, Guides and Books on the web.

Millions of people visit TecMint! If you like what you are reading, please consider buying us a coffee or 2 as a token of appreciation. We are thankful for your never ending support. There should be a way but we have to do a little research about this before we can give you a solution. Ho to do this? You would need to do this via a cron job. You would write a script, save it somewhere, and then trigger it via cron. The script would need to handle the logic of parsing the file into lines, parse the date from each line, and then discard the lines that have a date more than 30 days old.

Are the other methods working the same way? But there are other methods works same way as show in this article, I think you should give a try and see.. When I opened this link I was expecting ways to actually get rid of the file contents on the disk.

For device-level IO I'd say it's pretty unusual to use stdio. I'd strongly recommend using the lower-level open , read and write functions instead based on your later reply :. The underlying file itself, as seen by the kernel, is not buffered at this level. As others have pointed out, try not mixing the two. It sounds like what you are looking for is the fsync function or fdatasync? How are we doing? Please help us improve Stack Overflow. Take our short survey. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. How can you flush a write using a file descriptor?

Ask Question. Asked 13 years, 2 months ago. Active 5 years, 5 months ago. Viewed k times. In general a call to sync before you exit allows to flush file system buffers and can help a little.

To have an idea about how it can function you can see below. Since wait works with jobs as well as with PID numbers a lazy solution should be to put at the end of the script. More difficult is the situation if you run something that run something else in background because you have to search and wait if it is the case the end of all the child process: for example if you run a daemon probably it is not the case to wait it finishes From the help of wait :.

Thanks user , script is maybe the only thing that works in busybox! The shell was freezing for me after it, though. Looking for the cause, I found these big red warnings "don't use in a non-interactive shells" in script manual page :. When stdin is not a terminal for example: echo foo script , then the session can hang, because the interactive shell within the script session misses EOF and script has no clue when to close the session.

Normally it shouldn't be necessary, but with older versions there might be bash synchronization bugs on file descriptors. This is how I solve it:. I found that due to buffering when Mac OS X shuts down mytool never transfers the output to the sed command. However, if I execute sudo killall mytool , then mytool transfers the output to the sed command. In your case the output meaning your script has finished of your script redirected to that file. How are we doing? Please help us improve Stack Overflow.

Take our short survey. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams?

Collectives on Stack Overflow. Learn more. Force flushing of output to a file while bash script is still running Ask Question. Asked 12 years, 4 months ago. Active 8 months ago. Viewed k times. Improve this question. Nic 5, 8 8 gold badges 47 47 silver badges 66 66 bronze badges. We'll need to have a description -or if possible code- of what your small script does exactly To unbuffer python scripts you could use "python -u". To unbuffer perl scripts, see Greg Hewgill reply below.

Per-destination logfiles of deferred mail are maintained only for eligible destinations. This server implements the following requests: Tag Description add sitename queueid Inform the flush 8 server that the message with the specified queue ID is queued for the specified destination.

This request completes in the background. It does not talk to the network, and it does not talk to local users. The fast flush server can run chrooted at fixed low privilege.