When aliens invade Earth, be first to warn your neighbours by placing your computer screen at a window and executing this potentially Earth-saving command. Ctrl C when aliens are defeated.
to include hidden dirs use:
tree -adL 1
(with ls, requires 'ls -ad */ .*/')
Remounts a usb disk /dev/sdb, without having to physically remove and reinsert. (Gnome desktop)
for one line per process:
ss -p | cat
for established sockets only:
ss -p | grep STA
for just process names:
ss -p | cut -f2 -sd\"
or
ss -p | grep STA | cut -f2 -d\"
Get sopcast links for live sports from http://myp2p.eu (for example) Get sp-sc or sp-auth binary by googling (sopcast + linux) eg http://www.jbg.f2s.com/sp-sc.gz Requires the 32bit libstdc++5 package. After exiting mplayer, type 'killall sp-sc'
in place of warptv use shagadelictv, edgetv, agingtv, dicetv, vertigotv, revtv or quarktv (see 'gst-inspect-0.10 effectv'. Requires gstreamer-plugins-good (or gstreamer0.10-plugins-good ).
For slow webcams use something like
gst-launch-0.10 v4l2src ! video/x-raw-yuv,width=320,height=240 ! ffmpegcolorspace ! warptv ! ffmpegcolorspace ! autovideosink
.
For basic webcam view via gstreamer use
gst-launch-0.10 v4l2src ! autovideosink
emulates bash4's "echo {03..20}" Uses bash3 builtin function printf Show Sample Output
Flips the y-axis to emulate a real mirror, uses low resolution for speed, this will also hide blemishes and the like :)
Quick command to test your webcam. Press 'f' to toggle fullscreen. Can also use 'vlc v4l2://' if you want gui controls. For higher/smoother framerate lower the default resolution:
cvlc v4l2:// :v4l2-width=320 :v4l2-height=240 &
Launch a gui app remotely. In this example smplayer is installed on the remote machine, and movie.avi is in the remote user's home dir. Note that stdout/stderr is still local, so you'll have feedback locally, add '&>/dev/null' to suppress. This is surprisingly not well known (compared to running an X app locally via ssh -X). (NB. if your distro requires ~/.Xauthority file present, then try -fX if you have problems) Resubmitted (and trimmed, thanks sitaram) due to ridiculous voting on previous submission. Fingers crossed, it gets a better rating this time.
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
Show Sample Output
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
Show Sample Output
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
Show Sample Output
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.
Random quote from Borat -- no html parsing
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print a file on a single line
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Convert CSV to JSON
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Salvage a borked terminal
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11
Join a folder full of split files
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2
Execute a command on multiple hosts in parallel
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copies 20 most recently downloaded mp3 files (such as from Miro) into a directory
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Fetch the current human population of Earth
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Which processes are listening on a specific port (e.g. port 80)
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