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Write 200 blocks of 512k to a dummy file with dd, timing the result. The is useful as a quick test to compare the performance of different file systems.
dd can be used with /dev/zero to easily create a file of all zero-bytes. Pipe that through tr and use octal conversions to change the byte values from zero to 0xff (octal 0377). You can replace 0377 with the byte of your choice. You can also use \\0 and \\377 instead of the quoted version.
This version was mentioned in the comments. Credits go to flatcap.
The previously-posted one-liner didn't work for me for whatever reason, so I ended up doing this instead.
This command dumps a mounted disk to an ISO image. (Use "mount" to get the mounted disk's name.)
Make sure to un-mount the disk first.
Show running time. eta, progressbar
Create an image of "device" and send it to another machine through the network ("target" and "port" sets the ip and port the stream will be sent to), outputting a progress bar
On the machine that will receive, compress and store the file, use:
nc -l -p <port> | 7z a <filename> -si -m0=lzma2 -mx=9 -ms=on
Optionally, add the -v4g switch at the end of the line in order to split the file every 4 gigabytes (or set another size: accepted suffixes are k, m and g).
The file will be compressed using 7z format, lzma2 algorithm, with maximum compression level and solid file activated.
The compression stage will be executed on the machine which will store the image. It was planned this way because the processor on that machine was faster, and being on a gigabit network, transfering the uncompressed image wasn't much of a problem.
Same game as #10096 . loop as many times as you like.
Command to create a dummy file (full of nulls). Useful for testing e.g. file transfers when no file is at hand.
bs = blocksize, count = filesize in kilobytes
new way to replace text file with dd,faster than head,sed,awk if you do this with big file
create an iso from your cd/dvd-rom device . You need to umount /dev/cdrom
before using the cli
This will find any regular file starting with the current directory and use /dev/urandom to overwrite that file. It will is the same size of the file (in blocks) as the file. Can't handle files with spaces or odd characters in the name (who does that anyway?)
Have you ever wondered what the hell was dd command doing? well, there you have it... notice the -USR1 signal :)...
Especially useful to gauge the performance of a VPS.
Useful when you want to know the mbrid of a device - for the purpose of making it bootable. Certain hybridiso distros, for eg the OpenSUSE live ISO uses the mbrid to find the live media. Use this command to find out the mbrid of your USB drive and then edit the /grub/mbrid file to match it.
Only slightly different than previous commands. The benefit is that your "watch" should die when the dd command has completed. (Of course this would depend on /proc being available)
usage: mem memcache-command [arguments]
where memcache-command might be:
exptime argument is set to 0 (no expire)
flags argument is set to 1 (arbitrary)