Hide

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again.

Delete that bloated snippets file you've been using and share your personal repository with the world. 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.


If you have a new feature suggestion or find a bug, please get in touch via http://commandlinefu.uservoice.com/

Get involved!

You can sign-in using OpenID credentials, or register a traditional username and password.

First-time OpenID users will be automatically assigned a username which can be changed after signing in.

Hide

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:

Hide

News

2011-03-12 - Confoo 2011 presentation
Slides are available from the commandlinefu presentation at Confoo 2011: http://presentations.codeinthehole.com/confoo2011/
2011-01-04 - Moderation now required for new commands
To try and put and end to the spamming, new commands require moderation before they will appear on the site.
2010-12-27 - Apologies for not banning the trolls sooner
Have been away from the interwebs over Christmas. Will be more vigilant henceforth.
2010-09-24 - OAuth and pagination problems fixed
Apologies for the delay in getting Twitter's OAuth supported. Annoying pagination gremlin also fixed.
Hide

Tags

Hide

Functions

Commands tagged df from sorted by
Terminal - Commands tagged df - 10 results
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
2014-07-22 15:47:50
User: johnr
Functions: cut dd du tail tar tee
0

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 !

df -h --total | awk 'NR==1; END{print}'
diff <(cat /etc/fstab | grep vol | grep -v "^#" | awk '{print $1}') <(df -h | grep vol)
2014-01-23 15:18:08
User: Koobiac
Functions: awk cat df diff grep
Tags: diff fstab df
0

With this command, you can check the difference between the volumes mounted and the volume in /etc/fstab.

df | awk '{if ($2!=dspace) print "different"; dspace=$2;}'
df -h | grep -v ^none | ( read header ; echo "$header" ; sort -rn -k 5)
2011-03-16 14:25:45
User: purpleturtle
Functions: df echo grep read sort
Tags: sort headers df
0

Show disk space info, grepping out the uninteresting ones beginning with ^none while we're at it.

The main point of this submission is the way it maintains the header row with the command grouping, by removing it from the pipeline before it gets fed into the sort command. (I'm surprised sort doesn't have an option to skip a header row, actually..)

It took me a while to work out how to do this, I thought of it as I was drifting off to sleep last night!

du -sh ~/*
2010-11-05 10:20:16
Functions: du
1

Display the size (human reading) of all the directories in your home path (~).

df -l | grep -e "9.%" -e "100%"
2010-04-26 17:57:54
User: dooblem
Functions: df grep
2

Reports all local partitions having more than 90% usage.

Just add it in a crontab and you'll get a mail when a disk is full.

(sending mail to the root user must work for that)

tail $0 >> $0
2009-12-07 12:33:41
User: yooreck
Functions: tail
Tags: dd df
1

Put into some file. No special purpouse, just for fun...

dd if=/dev/zero of=/fs/to/fill/dummy00 bs=8192 count=$(df --block-size=8192 / | awk 'NR!=1 {print $4-100}')
2009-12-03 15:20:18
User: arcege
Functions: awk dd df
Tags: dd df
-3

For disk space constraint testing. Leaves a little space available for creating temp files, etc. Easily free up the used disk space again by deleting the dummy00 file. Can tailor the testing by building smaller 'blocks' to suit the needs of the testing.

WARNING: do not do this to the '/' (root) filesystem unless you know what you are doing... on some systems it could crash the OS.

find -L /proc/*/fd -links 0 2>/dev/null
2009-06-26 18:42:51
User: res0nat0r
Functions: find
Tags: du proc df
12

Oracle DBA remove some logfiles which are still open by the database and he is complaining the space has not been reclaimed? Use the above command to find out what PID needs to be stopped. Or alternatively recover the file via:

cp /proc/pid/fd/filehandle /new/file.txt