Commands by ppq (2)

  • If, for example, you want to remove all kernels and headers but the last three versions, you can't use one of that magic all-in-one "remove old stuff" commands. With this simple but elegant command you can remove a range of versions, or a list of versions with e.g. {14,16,20}. Show Sample Output

    apt purge linux*{14..18}*
    ppq · 2016-04-20 07:44:55 0
  • This is the fastest way to burn a DVD-Video from the command line. Dependencies: libav-tools dvdauthor growisofs The first command: avconv -i input.avi -target pal-dvd dvd.mpg converts any given video file avconv can handle into MPEG2-PS (6 Mbit/s) with AC3 audio (448 kbit/s). If your distribution is not up to date, just use ffmpeg - the syntax is the same. Hint: If you want to create an NTSC DVD, type ntsc-dvd instead ;-) The second command: echo PAL > ~/.config/video_format sets PAL as your default video format. This is a workaround for an old dvdauthor bug. If you want NTSC, guess what? Type NTSC instead! The third command: dvdauthor -o dvd/ -t dvd.mpg creates .VOB files and adds them to the dvd/ folder. You don't have to create this folder yourself. You can add as many titles as you like, just keep in mind that there's a maximum of 4482 MiB (4.37 GiB) for normal DVDs. The fourth command: dvdauthor -o dvd/ -T finishes the DVD-Video. Now you can burn your DVD using growisofs: growisofs -Z /dev/dvd -dvd-video dvd/ Sources: manpages

    avconv -i input.avi -target pal-dvd dvd.mpg && echo PAL > ~/.config/video_format && dvdauthor -o dvd/ -t dvd.mpg && dvdauthor -o dvd/ -T && growisofs -Z /dev/dvd -dvd-video dvd/
    ppq · 2012-09-09 20:56:54 0

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Simple server which listens on a port and prints out received data
Sometimes you need a simple server which listens on a port and prints out received data. Example: Consider you want to know, which data is posted by a homepage to a remote script without analysing the html code! A simple way to do this is to save the page to your computer, substitude all action="address" with action="localhost:portnumber", run 'ncat -l portnumber' and open the edited page with your browser. If you then submit the form, ncat will print out the http-protocol with all the posted data.

Access to specific man page section
You can view the man pages from section five by passing the section number as an argument to the man command

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" }

Fixes Centos 6.2 yum's metalink certificate errors
Fix's centos 6.2 yum's error: could not get metalink error was 14: PYCURL ERROR 77 - "Problem with the SSL CA cert (path? access rights?)" Error: Cannot retrieve metalink for repository: epel-source. Please verify its path and try again

Rename a file with a random name
Give files a random name (don't ask why :-) The function will rename files but maintain their extensions. BUG: If a file doesn't have an extension it will end up with a dot at the end of the name. The parameter '8' for pwgen controls the length of filenames - eight random characters.

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

convert single digit to double digits
each number in a file name gets expanded to the number of digets provided as arg_1 of the arguments in rjust_file_nums. Put the funciton in the .bashrc file. Be sure to $ source ~/.bashrc so that the function will be accessible from bash.

Analyze, check, auto-repair and optimize Mysql Database
A useful way to do a full check and auto repair damaged databases

Find the package that installed a command

See your current RAM frequency
man dmidecode [look for type]

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