Computer Notes/One Liners

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Platform: Windows

Command Line

  • Convert *.mkv files in folder B:\Videos to *.mp4 files in current folder[1]:
    • for /r "B:\Videos" %i in (*.mkv) do ffmpeg -i "%i" "%~ni.mp4"
  • Commands for ripping Dragon Ball DVDs:
    • for %i in (t*.mkv) do mkvmerge.exe -o _%i --default-track 2:no --default-track 3:yes --default-track 5:yes -a 2,3 -d 1 -s 5 %i --track-order 0:1,0:3,0:2,0:5
    • for %i in (t*.mkv) do mkvmerge.exe -o _%i --default-track 2:no --default-track 3:yes --default-track 4:yes -a 2,3 -d 1 -s 4 %i --track-order 0:1,0:3,0:2,0:4
    • grep TimeStart source.txt |sed -ne "1~5p" |sed -e "1d" |cut -d" " -f7 |tr "\n" ","

PuTTY[2]

  • Window
    • Lines of scrollback: 2000000
    • Check only:
      • Display scrollbar
      • Reset scrollback on keypress
      • Push erased text into scrollback
  • Window/Appearance
    • Font quality: ClearType
  • Window/Translation
    • Character set: UTF-8
    • Use Unicode line drawing code points
  • Connection
    • Seconds between keepalives: 25
  • Connection/Data
    • Terminal-type string: xterm-color
  • Connection/SSH
    • Enable compression

Videos to DVD

  • Install:
    • AVStoDVD 2.4.1
  • Configure AVStoDVD Labels.ini:
    • TitleFontSize: 30
    • ThumbsFontSize: 15
  • Configure AVStoDVD Preferences:
    • DVD Output/Assets Path
    • DVD Video Standard


  • Create DVD ISO:
    • Set DVD Label in "Settings".
    • Add files to Source Titles.
    • Set Output to "ISO UDF Image"
    • Create DVD Menu:
      • Still Pictures.
      • Set relevant aspect ratio.
      • Text Based Titles.
      • 5 titles per page.
      • Enable "Play All" Button.
    • Start.
  • If ISO is greater than 4450 MB:
    • Use DVD Shrink once or twice on the ISO.

Platform: Linux

Command Line

  • ip a
  • sshfs
  • knockd
  • ssh-copy-id
  • strings
  • at
  • service iptables save
  • netstat -tulpn
  • mutt
  • alternatives --config
  • /etc/aliases
  • grep --color
  • shopt -s histappend

Flush DNS Cache

  • service nscd reload
    • This fixed the weird problem where ping couldn't resolve hostnames but dig/host/wget could.

Dump HTTP Payload

  • tcpdump -i eth0 -s 0 -A 'tcp dst port 80 and (tcp[((tcp[12:1] & 0xf0) >> 2):4] = 0x504f5354)'

Convert TIFs to JPGs

  • mkdir convert &>/dev/null; for file in $(ls *.tif); do file_new="./convert/$(echo $file |sed "s/tif$/jpg/g")"; convert $file $file_new; exiftool -tagsFromFile $file $file_new; done

Find Duplicate Files

  • data=$(find . -type f -exec cksum {} \; |sort); data_uniq=$(echo -e "$data" |cut -d" " -f1 |uniq -d); for line in $(echo -e "$data_uniq"); do echo; echo -e "$data" |grep $line; done

Bash Colors[3]

txtblk='\e[0;30m' # Black - Regular
txtred='\e[0;31m' # Red
txtgrn='\e[0;32m' # Green
txtylw='\e[0;33m' # Yellow
txtblu='\e[0;34m' # Blue
txtpur='\e[0;35m' # Purple
txtcyn='\e[0;36m' # Cyan
txtwht='\e[0;37m' # White
bldblk='\e[1;30m' # Black - Bold
bldred='\e[1;31m' # Red
bldgrn='\e[1;32m' # Green
bldylw='\e[1;33m' # Yellow
bldblu='\e[1;34m' # Blue
bldpur='\e[1;35m' # Purple
bldcyn='\e[1;36m' # Cyan
bldwht='\e[1;37m' # White
unkblk='\e[4;30m' # Black - Underline
undred='\e[4;31m' # Red
undgrn='\e[4;32m' # Green
undylw='\e[4;33m' # Yellow
undblu='\e[4;34m' # Blue
undpur='\e[4;35m' # Purple
undcyn='\e[4;36m' # Cyan
undwht='\e[4;37m' # White
bakblk='\e[40m'   # Black - Background
bakred='\e[41m'   # Red
badgrn='\e[42m'   # Green
bakylw='\e[43m'   # Yellow
bakblu='\e[44m'   # Blue
bakpur='\e[45m'   # Purple
bakcyn='\e[46m'   # Cyan
bakwht='\e[47m'   # White
txtrst='\e[0m'    # Text Reset

MD

Replace RAID Disk

In this example, the scenario is /dev/sdd will be replaced with a larger capacity drive. NOTE: To see drive sizes: cat /proc/partitions |grep sd.1$

  • fdisk drive and partition as fd (Linux raid auto)
  • To get current state: mdadm --detail /dev/md0
  • Add the newly formatted partition to the array: mdadm /dev/md0 -a /dev/sdd1
  • Array will rebuild in the background: watch -n1 sudo mdadm --detail /dev/md0

Add RAID Disk

The scenario is that a new disk (5) will be added to the array, the device is /dev/sde.

  • fdisk drive and partition as fd (make sure all devices are the same type with fdisk -l)
  • Add the newly formatted partition to the array: mdadm /dev/md0 -a /dev/sdd1 (this will add it as a hot spare)
  • Find out the current number of active disks: mdadm --detail /dev/md0 (Active Devices)
  • Increment the number of active devices by one: mdadm --grow -n5 /dev/md0 (was 4, now 5) (with 5x1TB drives, this took 24 hours)
  • Update /etc/mdadm.conf by replacing the ARRAY line with the output of mdadm -Es

Grow RAID Device

NOTE: This section assumes you have the following drive layout: MD (linux software raid) -> LUKS (linux software full disk encryption encompassing the entire MD device) -> LVM (sitting directly on top of LUKS/dm-crypt).

After increasing the size of all hard disks, or adding another hard disk, do the following. The encrypted file system name was obtained from PV Name (/dev/mapper/luks-[...]) in /usr/sbin/pvdisplay

  • Grow the multi-disk device: mdadm --grow --size=max /dev/md0 (not necessary but doesn't hurt if md0 is already max)
  • Grow the encrypted file system: cryptsetup resize luks-5c9f9294-5a3c-4e5a-8180-f00821fecc46
  • Resize the LVM PV: pvresize /dev/mapper/luks-5c9f9294-5a3c-4e5a-8180-f00821fecc46
  • Run vgdisplay to verify the new VG Size, and get the current Free PE. In this example you see: Free PE / Size 95 / 2.97 GB
  • Expand the home logical volume: lvresize -l +95 /dev/vg0/home
  • Verify vgdisplay has 0 free PE, and lvdisplay shows /dev/vg0/home with the new size
  • Finally, expand the /home file system: resize2fs /dev/mapper/vg0-home (resizing from 3 TB to 4 TB took about an hour)

Platform: SunOS

Non-Truncated PS

  • /usr/ucb/ps auxwww

Platform: VMware ESX 3.5

Kill VM with vmid

  • killvm() { for a in "$@"; do /usr/lib/vmware/bin/vmkload_app -k 9 $(perl -ne 'print if s/.*vm\.(\d*).*/\1/' /proc/vmware/vm/$a/cpu/status); done; }

Get VMX path from vmid

  • function getvmx() { sed 's/.*cfgFile="\([^"]*\)".*/\1/' /proc/vmware/vm/$1/names ;}

Language: Python

Sorting a list by string length

mylist.sort(cmp=lambda x,y: len(x)-len(y))

Getting # of CPUs

  • os.sysconf('SC_NPROCESSORS_ONLN')

Dict string substitution[4]

LIGHT_MESSAGES = {
    'English': "There are %(number_of_lights)s lights.",
    'Pirate':  "Arr! There be %(number_of_lights)s lights."
}
def lights_message(language, number_of_lights):
    """Return a language-appropriate string reporting the light count."""
    return LIGHT_MESSAGES[language] % locals()

Misc

  • urls = [line.rstrip('\n\r') for line in f.readlines()]
  • self.COLS = curses.tigetnum('cols')
  • self.LINES = curses.tigetnum('lines')
  • struct.unpack('hh',fcntl.ioctl(0,termios.TIOCGWINSZ,'1234'))
  • return True if self.result[0] == 0 else False #python >= 2.5
  • return (self.result[0] == 0 and [True] or [False])[0] #python < 2.5

VIM

vimrc

  • colorscheme ron
  • set tabstop=4
  • set shiftwidth=4
  • set expandtab

Misc

  • Pretty XML:
    • %!xmllint --format -
  • Revert to last save:
    • :e!
  • Tabs to spaces:
    • retab

References

  1. ↑ http://stackoverflow.com/questions/659647/how-to-get-folder-path-from-file-path-with-cmd
  2. ↑ http://dag.wieers.com/blog/content/improving-putty-settings-on-windows
  3. ↑ https://wiki.archlinux.org/index.php/Color_Bash_Prompt
  4. ↑ http://stackoverflow.com/questions/56011/single-quotes-vs-double-quotes-in-python
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