Commands tagged mbuffer (1)

  • This will write to TAPE (LTO3-4 in my case) a backup of files/folders. Could be changed to write to DVD/Blueray. Go to the directory where you want to write the output files : cd /bklogs Enter a name in bkname="Backup1", enter folders/files in tobk="/home /var/www". It will create a tar and write it to the tape drive on /dev/nst0. In the process, it will 1) generate a sha512 sum of the tar to $bkname.sha512; so you can validate that your data is intact 2) generate a filelist of the content of the tar with filesize to $bkname.lst 3) buffer the tar file to prevent shoe-shining the tape (I use 4GB for lto3(80mb/sec), 8gb for lto4 (120mb/sec), 3Tb usb3 disks support those speed, else I use 3x2tb raidz. 4) show buffer in/out speed and used space in the buffer 5) show progress bar with time approximation using pv ADD : To eject the tape : ; sleep 75; mt-st -f /dev/nst0 rewoffl TODO: 1) When using old tapes, if the buffer is full and the drive slows down, it means the tape is old and would need to be replaced instead of wiping it and recycling it for an other backup. Logging where and when it slows down could provide good information on the wear of the tape. I don't know how to get that information from the mbuffer output and to trigger a "This tape slowed down X times at Y1gb, Y2gb, Y3gb down to Zmb/s for a total of 30sec. It would be wise to replace this tape next time you want to write to it." 2) Fix filesize approximation 3) Save all the output to $bkname.log with progress update being new lines. (any one have an idea?) 4) Support spanning on multiple tape. 5) Replace tar format with something else (dar?); looking at xar right now (https://code.google.com/p/xar/), xml metadata could contain per file checksum, compression algorithm (bzip2, xv, gzip), gnupg encryption, thumbnail, videopreview, image EXIF... But that's an other project. TIP: 1) You can specify the width of the progressbar of pv. If its longer than the terminal, line refresh will be written to new lines. That way you can see if there was speed slowdown during writing. 2) Remove the v in tar argument cvf to prevent listing all files added to the archive. 3) You can get tarsum (http://www.guyrutenberg.com/2009/04/29/tarsum-02-a-read-only-version-of-tarsum/) and add >(tarsum --checksum sha256 > $bkname_list.sha256) after the tee to generate checksums of individual files !


    0
    bkname="test"; tobk="*" ; totalsize=$(du -csb $tobk | tail -1 | cut -f1) ; tar cvf - $tobk | tee >(sha512sum > $bkname.sha512) >(tar -tv > $bkname.lst) | mbuffer -m 4G -P 100% | pv -s $totalsize -w 100 | dd of=/dev/nst0 bs=256k
    johnr · 2014-07-22 15:47:50 8

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands


Check These Out

Adding Prefix to File name
Adding course name prefix to lecture pdfs

Rename all subtitles files with the same name of mp4 files in same folder
Use this command if you want to rename all subtitles for them to have the same name as the mp4 files. NOTE: The order of "ls -1 *.mp4" must match the order of "ls -1 *.srt", run the command bellow to make sure the *.srt files will really match the movies after run this command: paste -d:

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Google Translate
$ translate [output-language] [source-language] 1) "some phrase" should be in quotes 2) [output-language] - optional (default: English) 3) [source-language] - optional (default: auto) $ translate "bonjour petit lapin" hello little rabbit $ translate "bonjour petit lapin" en hello little rabbit $ translate "bonjour petit lapin" en fr hello little rabbit

Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)
Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.

Check if the LHC has destroyed the world
This says if the LHC has destroyed the world. Run it in a loop to monitor the state of Earth. Might not work reliable, if the world has actually been destroyed.

Use socat to emulate an SMTP mail SERVER
Lots of scripts show you how to use socat to send an email to an SMTP server; this command actually emulates an SMTP server! It assumes the client is only sending to one recipient, and it's not at all smart, but it'll capture the email into a log file and the client will stop retrying. I used this to diagnose what emails were being sent by cron and subsequently discarded, but you can use it for all sorts of things.

find the rpm package name that provides a specific file
For Linux distributions using rpm (eg Mandriva), this command will find the rpm package name that provides a file.

Redirect STDIN
Several times, I find myself hitting my up arrow, and changing the search term. Unfortunately, I find myself wasting too much time typing: $ grep kernel /var/log/messages Redirecting STDIN allows me to put the search term at the end so I less cursor movement to change what I'm searching for: $ < /var/log/messages grep kernel If you're using the emacs keyboard binding, then after you press your up arrow, press CTRL+w to erase the word. If this has already been submitted, I couldn't find it with the search utility.

dd with progress bar and statistics
Will automatically take the size of the file but longer, usefull only if in an function.


Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: