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Extract audio from Mythtv recording to Rockbox iPod using ffmpeg

There are some pretty good live performances on late night TV. With Mythtv I record David Letterman, Jimmy Fallon, and Conan nightly all in HD from over the air broadcasts. If I find a live performance I like I copy it to my Rockboxed iPod using this command. The Rockbox firmware knows how to downmix 5.1 audio. The command above extracts the audio from the video starting at 58 minutes and 15 seconds. It ends at the end of the file since this was the last performance of the recording. The command creates an ac3 file. I copy the ac3 file to my Rockbox iPod and rock on.
This is sample output - yours may be different.
3

ffmpeg -ss 0:58:15 -i DavidLettermanBlackCrowes.mpg -acodec copy DavidLettermanBlackCrowes.ac3

PLA · 2009-09-14 00:08:36 3
preprocess code to be posted in comments on this site

Assuming that $script contains the filename of a script you'd like to post as part of a comment on this site, this will prefix each line with '$' and pipe it into the X selection. From there just put the cursor in the right place in the comments box and middle-click. Should work pretty much anywhere with xclip installed. On debian-ish systems this is installed as part of the package "xclip".
This is sample output - yours may be different.
2

sed 's/^/$ /' "$script" | xclip

intuited · 2009-09-13 11:21:54 31
List symbols from a dynamic library (.so file)

You can get what functions at which addresses are inside a dynamic link library by this tool.
This is sample output - yours may be different.
2

nm --dynamic <libfile.so>

Vereb · 2009-09-13 09:27:57 11
send echo to socket network

Using netcat, usuallly installed on debian/ubuntu. Also to test against a sample server the following two commands may help echo got milk? | netcat -l -p 25 python -c "import SocketServer; SocketServer.BaseRequestHandler.handle = lambda self: self.request.send('got milk?\n'); SocketServer.TCPServer(('0.0.0.0', 25), SocketServer.BaseRequestHandler).serve_forever()" Show Sample Output
This is sample output - yours may be different.
```
got milk?
```
2

echo foo | netcat 192.168.1.2 25

pykler · 2009-09-13 01:33:02 4
Start an X app remotely

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.
This is sample output - yours may be different.
7

ssh -f user@remote.ip DISPLAY=:0.0 smplayer movie.avi

Escher · 2009-09-12 22:16:59 13
send echo to socket network

this command will send a message to the socket 25 on host 192.168.1.2 in tcp. works on udp and icmp understand only IP address, not hostname. on the other side (192.168.1.2), you can listen to this socket and test if you receive the message. easy to diagnose a firewall problem or not.
This is sample output - yours may be different.
25

echo "foo" > /dev/tcp/192.168.1.2/25

mobidyc · 2009-09-12 16:48:05 16
find only current directory (universal)

you must be in the directory to analyse report all files and links in the currect directory, not recursively. this find command ahs been tested on hp-ux/linux/aix/solaris. Show Sample Output
This is sample output - yours may be different.
```
find . $ ! -name . -prune $ $ -type f -o -type l $
./bosinst.data
./smit.log
./lib
```
1

find . $ ! -name . -prune $ $ -type f -o -type l $

mobidyc · 2009-09-12 15:58:56 11
FLV to AVI with subtitles and forcing audio sync using mencoder

Gives MPEG-4/DivX output video file ready for uploading to YouTube from FLV file downloaded from the site and your own subtitle file UTF-8 encoded. No resizing needed. (?)
This is sample output - yours may be different.
1

mencoder -sub subs.ssa -utf8 -subfont-text-scale 4 -oac mp3lame -lameopts cbr=128 -ovc lavc -lavcopts vcodec=mpeg4 -ffourcc xvid -o output.avi input.flv

ivalladt · 2009-09-12 09:24:24 5
search for a file in PATH
This is sample output - yours may be different.
1

which <filename>

Hal_Pomeranz · 2009-09-12 00:51:24 5
Dump dvd from a different machine onto this one.

You can use this to directly dump from machine A (with dvd drive) to machine B (without dvd drive) . I used this to copy dvd using my friend's machine to my netbook. Above command is to be issued on machine B. Advantages : 1) No wasting time dumping first to machine A and then copying to Machine B. 2) You dont need to use space on Machine A. In fact, this will work even when Machine A doesnt have enough hdd space to dump the DVD. Use -C ssh option on slow networks (enables compression). you can replace "dd if=/dev/dvd" with any ripping command as long as it spews the iso to stdout.
This is sample output - yours may be different.
5

ssh user@machine_A dd if=/dev/dvd0 > dvddump.iso

kamathln · 2009-09-11 18:08:36 12
Create multiple mp4 files using avidemux

Convert multiple files using avidemux. Version updated (thanks to the guys who helped me giving me hints about how to improve the command). Works with files whose name contains blank characters. One of the reasons why I love open source: everyone can take something "done" and improve it to make it better! If u have suggestions, please let me know.
This is sample output - yours may be different.
2

for i in *;do avidemux --video-codec Xvid4 --audio-codec mp3 --load "${i}" --save "`echo "$i" | sed -e 's/\....$//'`.done.mp4" --quit; done

gean01 · 2009-09-11 17:07:38 3
How far is Mac OS X 10.6 from 64-bit?

Not as far off as you thought, now is it? -mac fanboy Show Sample Output
This is sample output - yours may be different.
```
127	Mach-O 64-bit kext bundle x86_64
140	Mach-O object i386
```
-2

file /System/Library/Extensions/*.kext/Contents/MacOS/* |grep -i x86_64 |nl | tail -1 | cut -f1 -f3; file /System/Library/Extensions/*.kext/Contents/MacOS/* |grep -i "mach-o object i386" |nl | tail -1 | cut -f1 -f3

digitalshadow · 2009-09-11 16:43:27 4
search for a file in PATH

Searches in order of the directories of $PATH. Stops after finding the entry; looks for only that fileName. Works in Bourne, Korn, Bash and Z shells. Show Sample Output
This is sample output - yours may be different.
```
/usr/local/bin/fileName
```
-1

for L in `echo :$PATH | tr : '\n'`; do F=${L:-"."}/fileName; if [ -f ${F} -o -h ${F} ]; then echo ${F}; break; fi; done

arcege · 2009-09-11 16:14:36 3
Ultimate current directory usage command

A little bit smaller, faster and should handle files with special characters in the name.
This is sample output - yours may be different.
1

find . -maxdepth 1 ! -name '.' -execdir du -0 -s {} + | sort -znr | gawk 'BEGIN{ORS=RS="\0";} {sub($1 "\t", ""); print $0;}' | xargs -0 du -hs

ashawley · 2009-09-11 16:07:39 7
Identify differences between directories (possibly on different servers)

This can be much faster than downloading one or both trees to a common servers and comparing the files there. After, only those files could be copied down for deeper comparison if needed. Show Sample Output
This is sample output - yours may be different.
```
5,7c7,9
< 5955632baf6598bd56668bf45aae31c3  ./hibernate.properties
< 54ba5e4ebe18ef4855fa2796dfb2521e  ./logging.xml
< 388a7f1823574252e26ddbdbd68a02bf  ./manager.properties
---
> 165768e0b454c90ab1b26150b7954fd2  ./hibernate.properties
> 0ad95a5ab764bfdede2dc713f84ecfc0  ./logging.xml
> 636d9444bc20ffe2dc2433b90b2535e7  ./manager.properties
```
14

diff <(ssh server01 'cd config; find . -type f -exec md5sum {} \;| sort -k 2') <(ssh server02 'cd config;find . -type f -exec md5sum {} \;| sort -k 2')

arcege · 2009-09-11 15:24:59 9
no more line wrapping in your terminal

works on all unices. Show Sample Output
This is sample output - yours may be different.
```
ps auxwww |nowrap
```
4

function nowrap { export COLS=`tput cols` ; cut -c-$COLS ; unset COLS ; }

mobidyc · 2009-09-11 15:07:00 13
search for a file in PATH

search argument in PATH accept grep expressions without args, list all binaries found in PATH Show Sample Output
This is sample output - yours may be different.
```
$ sepath noo
/usr/openwin/bin/ttsnoop
/usr/sbin/snoop
$ sepath ^ps$
/bin/ps
/usr/bin/ps
/usr/ucb/ps
```
-1

function sepath { echo $PATH |tr ":" "\n" |sort -u |while read L ; do cd "$L" 2>/dev/null && find . $ ! -name . -prune $ $ -type f -o -type l $ 2>/dev/null |sed "s@^\./@@" |egrep -i "${*}" |sed "s@^@$L/@" ; done ; }

mobidyc · 2009-09-11 15:03:22 5
Output files without comments or empty lines

better integration. works on all Unices works one bash and ksh. Show Sample Output
This is sample output - yours may be different.
```
$ catv /tmp/test
foo
$ cat /tmp/test |catv
foo
$ cat  /tmp/test
foo
# comment
#bar
```
1

function catv { egrep -v "^$|^#" ${*} ; }

mobidyc · 2009-09-11 14:58:47 3
Simple Comment an entire file

With this simple sed command we can easily comment and entire file.
This is sample output - yours may be different.
1

sed -i 's/^/#/' FILENAME

flip387 · 2009-09-11 14:13:47 25
The end of 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
This is sample output - yours may be different.
```
Tue Jan 19 03:14:07 UTC 2038
```
-149

date -ud @$[2**31-1]

Escher · 2009-09-11 08:48:50 8
connect via ssh using mac address

Instead of looking for the right ip address, just pick whatever address you like and set a static ip mapping.
This is sample output - yours may be different.
7

sudo arp -s 192.168.1.200 00:35:cf:56:b2:2g temp && ssh root@192.168.1.200

svg · 2009-09-11 07:49:28 8
print scalar gmtime

print scalar gmtime
This is sample output - yours may be different.
0

perl -e "print scalar(gmtime(1247848584))"

opexxx · 2009-09-11 06:19:09 17
Run remote web page, but don't save the results

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.
This is sample output - yours may be different.
0

wget -q --spider http://server/cgi/script

ashawley · 2009-09-11 05:33:48 3
Mount an ISO image on Mac OS X
This is sample output - yours may be different.
0

hdiutil mount sample.iso

mgorovoy · 2009-09-11 05:02:56 3
Display the standard deviation of a column of numbers with awk

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.
This is sample output - yours may be different.
4

awk '{delta = $1 - avg; avg += delta / NR; mean2 += delta * ($1 - avg); } END { print sqrt(mean2 / NR); }'

ashawley · 2009-09-11 04:46:01 5
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generate random ascii shape(no x11 needed!)

Command line calculator

This opens a python command line. You can use math and random and float-division is enabled (without appending .0 to integers). I just don't know how to specify a standard precision.

clear MyDNS-ng cache

Occasionally, to force zone updating, cache flush is necessary. This command is better than restart the mydns daemon.

To print a specific line from a file

Just one character longer than the sed version ('FNR==5' versus -n 5p). On my system, without using "exit" or "q", the awk version is over four times faster on a ~900K file using the following timing comparison: $ testfile="testfile"; for cmd in "awk 'FNR==20'" "sed -n '20p'"; do echo; echo $cmd; eval "$cmd $testfile"; for i in {1..3}; do time for j in {1..100}; do eval "$cmd $testfile" >/dev/null; done; done; done Adding "exit" or "q" made the difference between awk and sed negligible and produced a four-fold improvement over the awk timing without the "exit". For long files, an exit can speed things up: $ awk 'FNR==5{print;exit}'

list block devices

Shows all block devices in a tree with descruptions of what they are.

create directory and set owner/group/mode in one shot

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" }

Show crontabs for all users

added echo "### Crontabs for $user ####"; to make clear whose crontab is listed.

Cropping a video file in ffmpeg

burn initial session on a growable DVD using growisofs

replace "directory name to burn on DVD" with actual directory name that you want to copy on DVD

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