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Terminal - All commands - 12,428 results
sed -i 's/^/#/' FILENAME
2009-09-11 14:13:47
User: flip387
Functions: sed
1

With this simple sed command we can easily comment and entire file.

date -ud @$[2**31-1]
2009-09-11 08:48:50
User: Escher
Functions: date
-148

The end of unix time and the 32bit era will be Tue Jan 19 03:14:07 UTC 2038

.

date -ud @$[2**31]

date: invalid date `@2147483648'

.

In 64bit you have much longer, at least to:

date -ud @$[2**55] Sun Jun 13 06:26:08 UTC 1141709097
sudo arp -s 192.168.1.200 00:35:cf:56:b2:2g temp && ssh [email protected]
2009-09-11 07:49:28
User: svg
Functions: arp ssh sudo
7

Instead of looking for the right ip address, just pick whatever address you like and set a static ip mapping.

perl -e "print scalar(gmtime(1247848584))"
2009-09-11 06:19:09
User: opexxx
Functions: perl
Tags: perl
0

print scalar gmtime

wget -q --spider http://server/cgi/script
2009-09-11 05:33:48
User: ashawley
Functions: wget
Tags: wget
0

I don't know if the --spider option works to execute a script, but it might be worth trying. Note that the Drupal project uses the following in a cron job.

wget -O - -q http://localhost/drupal/cron.php

The output is sent to standard out so it can be logged by cron.

hdiutil mount sample.iso
awk '{delta = $1 - avg; avg += delta / NR; mean2 += delta * ($1 - avg); } END { print sqrt(mean2 / NR); }'
2009-09-11 04:46:01
User: ashawley
Functions: awk delta
Tags: awk
4

This will calculate a running standard deviation in one pass and should never have the possibility for overflow that can happen with other implementations. I suppose there is a potential for underflow in the corner case where the deltas are small or the values themselves are small.

echo "vertical text" | grep -o '.'
2009-09-11 03:45:04
User: dennisw
Functions: echo grep
12

Define a function

vert () { echo $1 | grep -o '.'; }

Use it to print some column headers

paste <(vert several) <(vert parallel) <(vert vertical) <(vert "lines of") <(vert "text can") <(vert "be used") <(vert "for labels") <(vert "for columns") <(vert "of numbers")
mencoder -oac mp3lame -lameopts cbr=128 -ovc xvid -xvidencopts bitrate=1200 inputfile.rmvb -o output.avi
python fsrecovery.py -P 0 -f <path-to-instance>/Data.fs <path-to-instance-destination>/Data.fs.packed
for IP in $(/sbin/ifconfig | fgrep addr: | sed 's/.*addr:\([[0-9.]*\) .*/\1/') ; do host $IP | awk '{print $5}'; done
awk '{avg += ($1 - avg) / NR;} END { print avg; }'
2009-09-10 17:06:03
User: ashawley
Functions: awk
6

This is an on-line algorithm for calculating the mean value for numbers in a column. Also known as "running average" or "moving average".

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
7

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
3

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
-134

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:

F(2n-1)=Fn*Fn+F(n-1)*F(n-1)

F(2n)=(Fn+2*F(n-1))*Fn

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
-135

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:

F(2n-1)=Fn*Fn+F(n-1)*F(n-1)

F(2n)=Fn*(2*F(n-1)+Fn)

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
8

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
16

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
-5

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
5

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
-12

Display man page in plain text

help
2009-09-10 00:43:31
User: suxer
-8

for bash commands don't use man use help