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May 19, 2015 - A Look At The New Commandlinefu
I've put together a short writeup on what kind of newness you can expect from the next iteration of clfu. Check it out here.
March 2, 2015 - New Management
I'm Jon, I'll be maintaining and improving clfu. Thanks to David for building such a great resource!

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Psst. Open beta.

Wow, didn't really expect you to read this far down. The latest iteration of the site is in open beta. It's a gentle open beta-- not in prime-time just yet. It's being hosted over at UpGuard (link) and you are more than welcome to give it a shot. Couple things:

  • » The open beta is running a copy of the database that will not carry over to the final version. Don't post anything you don't mind losing.
  • » If you wish to use your user account, you will probably need to reset your password.
Your feedback is appreciated via the form on the beta page. Thanks! -Jon & CLFU Team

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Terminal - All commands - 12,392 results
for db in $(mysql -e 'show databases' -s --skip-column-names); do mysqldump $db | gzip > "/backups/mysqldump-$(hostname)-$db-$(date +%Y-%m-%d-%H.%M.%S).gz"; done
ffmpeg -i inputfile.mp4 outputfile.flv
2009-09-10 14:49:14
Tags: ffmpeg convert

This converts any media ffmpeg handles to flash. It would actually convert anything to anything, it's based on the file extension. It doesn't do ANY quality control, sizing, etc, it just does what it thinks is best. I needed an flv for testing, and this spits one out easily.

perl -lne '$l{$_}=length;END{for(sort{$l{$a}<=>$l{$b}}keys %l){print}}' < /usr/share/dict/words | tail
wget -O /dev/null http://www.google.com
2009-09-10 14:43:57
Functions: wget
Tags: wget

I have a remote php file that I want to run once an hour. I set up cron to run this wget. I don't really care about what's in the file though, I don't want to save the results, so I run the -O and send it to /dev/null

time echo 'n=1000000;m=(n+1)/2;a=0;b=1;i=0;while(m){e[i++]=m%2;m/=2};while(i--){c=a*a;a=c+2*a*b;b=c+b*b;if(e[i]){t=a;a+=b;b=t}};if(n%2)a*a+b*b;if(!n%2)a*(a+2*b)' | bc
2009-09-10 09:00:44
User: Escher
Functions: echo time

EDIT: Trolling crap removed ;)

takes approx 6 secs on a Core 2 Duo @ 2GHz, and 15 secs on atom based netbooks!

uses monoid (a,b).(x,y)=(ax+bx+ay,ax+by) with identity (0,1), and recursion relations:



then apply fast exponentiation to (1,0)^n = (Fn,F(n-1))


Note that: (1,0)^-1=(1,-1) so (a,b).(1,0) = (a+b,a) and (a,b)/(1,0)=(a,b).(1,0)^-1=(b,a-b)

So we can also use a NAF representation to do the exponentiation,http://en.wikipedia.org/wiki/Non-adjacent_form , it's also very fast (about the same, depends on n):

time echo 'n=1000000;m=(n+1)/2;a=0;b=1;i=0;while(m>0){z=0;if(m%2)z=2-(m%4);m=(m-z)/2;e[i++]=z};while(i--){c=a*a;a=c+2*a*b;b=c+b*b;if(e[i]>0){t=a;a+=b;b=t};if(e[i]<0){t=a;a=b;b=t-b}};if(n%2)a*a+b*b;if(!n%2)a*(a+2*b)' | bc
time echo 'n=70332;m=(n+1)/2;a=0;b=1;i=0;while(m){e[i++]=m%2;m/=2};while(i--){c=a*a;a=c+2*a*b;b=c+b*b;if(e[i]){t=a;a+=b;b=t}};if(n%2)a*a+b*b;if(!n%2)a*(a+2*b)' | bc
2009-09-10 08:58:47
User: Escher
Functions: echo time

Calculates nth Fibonacci number for all n>=0, (much faster than matrix power algorithm from http://everything2.com/title/Compute+Fibonacci+numbers+FAST%2521 )

n=70332 is the biggest value at http://bigprimes.net/archive/fibonacci/ (corresponds to n=70331 there), this calculates it in less than a second, even on a netbook.

UPDATE: Now even faster! Uses recurrence relation for F(2n), see http://en.wikipedia.org/wiki/Fibonacci_number#Matrix_form

n is now adjusted to match Fn at wikipedia, so bigprimes.net table is offset by 1.

UPDATE2: Probably fastest possible now ;), uses a simple monoid operation:

uses monoid (a,b).(x,y)=(ax+bx+ay,ax+by) with identity (0,1), and recursion relations:



then apply fast exponentiation to (1,0)^n = (Fn,F(n-1))


Note that: (1,0)^-1=(1,-1) so (a,b).(1,0) = (a+b,a) and (a,b)/(1,0)=(a,b).(1,0)^-1=(b,a-b)

So we can also use a NAF representation to do the exponentiation,http://en.wikipedia.org/wiki/Non-adjacent_form , it's also very fast (about the same, depends on n):

time echo 'n=70332;m=(n+1)/2;a=0;b=1;i=0;while(m>0){z=0;if(m%2)z=2-(m%4);m=(m-z)/2;e[i++]=z};while(i--){c=a*a;a=c+2*a*b;b=c+b*b;if(e[i]>0){t=a;a+=b;b=t};if(e[i]<0){t=a;a=b;b=t-b}};if(n%2)a*a+b*b;if(!n%2)a*(a+2*b)' | bc
PS3="Enter a number: "; select f in *;do $EDITOR $f; break; done
2009-09-10 06:04:42
User: haivu
Tags: bash

This command displays a simple menu of file names in the current directory. After the user made a choice, the command invokes the default editor to edit that file.

* Without the break statement, the select command will loop forever

* Setting the PS3 prompt is optional

* If the user types an invalid choice (such as the letter q), then the variable $f will become an empty string.

* For more information, look up the bash's select command

awk 'length>72' file
2009-09-10 05:54:41
User: haivu
Functions: awk
Tags: awk

This command displays a list of lines that are longer than 72 characters. I use this command to identify those lines in my scripts and cut them short the way I like it.

exiftool -DateTimeOriginal='2009:01:01 02:03:04' file.jpg
gcc -x c -o /tmp/out - -lgmp <<< '#include <stdlib.h> ... SEE SAMPLE OUTPUT FOR FULL COMMAND
2009-09-10 02:10:46
User: hank
Functions: c++ gcc

It's hard to beat C. This is just slightly faster than the bc version on my machine.

real 0m26.856s

user 0m25.030s

sys 0m0.024s

Requirements: libgmp headers, gcc.

for i in `ls`;do avidemux --video-codec Xvid4 --load $i --save $i.mp4 --quit; done
2009-09-10 01:38:42
User: gean01

Using avidemux to convert multiple files that are in the folder where the command was executed.

man bash | col -b
2009-09-10 00:45:27
User: suxer
Functions: bash col man

Display man page in plain text

2009-09-10 00:43:31
User: suxer

for bash commands don't use man use help

dd if=/dev/zero of=/dev/fd0 bs=512 count=1
2009-09-09 23:43:22
User: andrew112358
Functions: dd

Overwrites the boot sector. Since this doesn't overwrite any data, you can usually recover by re-creating the partition table exactly the same as before you zeroed it. This can also help sometimes if you install a new drive in a Windows machine which can't read it.

curl -u username --silent "https://mail.google.com/mail/feed/atom" | perl -ne 'print "\t" if /<name>/; print "$2\n" if /<(title|name)>(.*)<\/\1>/;
2009-09-09 23:25:05
User: suxer
Functions: perl

notice what happens when there is more than one unread message in a thread...

also people please dont hardcode the password when you use curl. Leave it out and curl will ask you when it runs. Please...?

iptables -t nat -A POSTROUTING -p tcp --dport 25 -j SNAT --to-source IP_TO_ROUTE_THROUGH
svn propset svn:ignore "*" tool/templates_c; svn commit -m "Ignoring tool/templates_c"
2009-09-09 19:10:03
User: lawrence

This command allow you to ignore certain directories on SVN commands, like SVN STATUS. It is sad see a lot of temporary files from templates_c for each "svn status", no? ;-)

This works only on directories under revision control.

cat /var/lib/dpkg/info/*.list > /tmp/listin ; ls /proc/*/exe |xargs -l readlink | grep -xvFf /tmp/listin; rm /tmp/listin
2009-09-09 18:09:14
User: kamathln
Functions: cat grep ls readlink rm xargs
Tags: Debian find dpkg

This helped me find a botnet that had made into my system. Of course, this is not a foolproof or guarantied way to find all of them or even most of them. But it helped me find it.

explorer .
ack -ai 'searchterm'
screen -x
2009-09-09 11:30:56
User: flart
Functions: screen

Force the user you want to watch doing things into doing his things in a screen session. Then simply attach yourself to that session with the command shown above.

Works only if you are on the same machine, of course

xdg-open .
2009-09-09 07:20:32
User: karpoke
Tags: xdg-open

Opens a file or URL in the user's preferred application.

echo -e "${PATH//://\n}" >/tmp/allpath; grep -Fh -f /tmp/allpath /var/lib/dpkg/info/*.list|grep -vxh -f /tmp/allpath >/tmp/installedinpath ; find ${PATH//:/ } |grep -Fxv -f /tmp/installedinpath
2009-09-09 05:33:14
User: kamathln
Functions: echo find grep
Tags: Debian dpkg PATH

OS: Debian based (or those that use dpkg)

Equivalent to doing a dpkg -S on each file in $PATH, but way faster.

May report files generated though postinstall scripts and such. For example . It will report /usr/bin/vim .. which is not not a file installed directly by dpkg, but a link generated by alternatives hooks

gnome-open .
ssh root@`for ((i=100; i<=110; i++));do arp -a 192.168.1.$i; done | grep 00:35:cf:56:b2:2g | awk '{print $2}' | sed -e 's/(//' -e 's/)//'`
2009-09-09 04:32:20
User: gean01
Functions: arp awk grep sed ssh

Connect to a machine running ssh using mac address by using the "arp" command