Commands by omap7777 (5)

  • IMPORTANT: You need Windows PowerShell to run this command - in your Windows Command Prompt, type powershell Uses sajb to start a PowerShell background job that pings an IP host every 10 seconds. Any changes in the host's Up/Down state is time-stamped and logged to a file. Date/time stamps are logged in two formats: Unix and human-readable. A while(1) loop repeats the test every 10 seconds by using the sleep command. See the Sample Output for more detail. I use this command to log Up/Down events of my Motorola SB6141 cable modem (192.168.100.1). To end the logging, close the PowerShell window or use the "exit" command. Show Sample Output


    0
    sajb {$ip="192.168.100.1";$old=0;while(1){$up=test-connection -quiet -count 1 $ip;if($up-ne$old){$s=(date -u %s).split('.')[0]+' '+(date -f s).replace('T',' ')+' '+$ip+' '+$(if($up){'Up'}else{'Down'});echo $s|out-file -a $home\ping.txt;$old=$up}sleep 10}}
    omap7777 · 2015-12-28 20:33:08 15
  • IMPORTANT: You need Windows PowerShell to run this command - in your Windows Command Prompt, type powershell Create a log file of your Motorola Surfboard SB6141 downstream signal strengths. Uses the built-in curl to request signal strength data from your SB6141 cable modem. HTML page 192.168.100.1/cmSignalData.htm has the signal strength numbers for the 8 downstreams. Some HTML/DOM processing parses out the 8 values from the above page. The eight extracted signal strengths are then logged to a file. A small while-loop watches the clock & repeats the process every 10 seconds. Show Sample Output


    0
    while(1){while((date -f ss)%10-gt0){sleep -m 300} echo "$(date -u %s) $((curl 192.168.100.1/cmSignalData.htm).parsedhtml.body.childnodes.item(1).firstchild.firstchild.childnodes.item(5).outertext|%{$_ -replace '\D+\n',''})">>modemlog.txt;sleep 1;echo .}
    omap7777 · 2015-12-24 02:12:10 11
  • An old USB A/B cable is all you need to make your own Smart Home hardware! Cut off and discard the B-portion of the USB cable. On the A side, connect the RED (+) and WHITE (D-) wires via a 1 kiloohm resistor. Picture: http://imgur.com/dJGVlAU Now plug the cable into a USB port on your Linux computer. Your hardware is ready! Run the above command after changing variable mysms to your personal email-to-SMS gateway info as required by your cellular service provider. The command uses the amazing usbmon tool (see link below) to detect the cable. For the curious, to view the raw usbmon output, run this command: (Also see the sample output) usbmon -i usb0 How does it work? When the red and white wires are connected (via the 1 kiloohm resistor) the USB hardwere is tricked into thinking that a new USB device is trying to start up. We then use the usbmon utility to capture the host USB events as it tries to talk to the cable. The expect utility watches the usbmon stream and waits for the disconnect text "-2:128" before sending the SMS message. Finally, the sendmail tool is used to email the SMS message to your smartphone via your cellular provider's SMS-to-email gateway. As a result, when the electrical connection between the red and white wire is interrupted, or the USB cable is unplugged from your computer, you get an SMS notification of the disconnect event on your smartphone. Could this be the cheapest smart home gadget ever? What are YOU going to sense with it? Please let me know in the comments and please don't forget to click it up! Links: http://www.linuxcertif.com/man/8/usbmon/ http://en.wikipedia.org/wiki/USB#Pinouts http://imgur.com/dJGVlAU Show Sample Output


    5
    mysms='xxx0001234@messaging.sprintpcs.com' ; expect -c "log_user 0 ; set timeout -1 ; spawn usbmon -i usb0 ; expect -re \"C.*Ii.*-2:128\" { spawn sendmail $mysms ; send \"Smart Home Sensor Triggered\n.\n\" ; expect }"
    omap7777 · 2015-05-02 06:10:10 14
  • Uses the lm-sensors package in Linux to display fan speed. Grep RPM is used to discover lines containing the text RPM, and sed is used to edit out everything but the RPM number. The watch utility is used to update the display every 10 seconds and -d highlights any changes from the previous value. The eval function of Bash is used to execute the command enclosed in the ".." string. Show Sample Output


    1
    watch -n 10 -d eval "sensors | grep RPM | sed -e 's/.*: *//;s/ RPM.*//'"
    omap7777 · 2015-04-07 14:28:32 9
  • Uses the extremely cool utilities netcat and expect. "expect" logs in & monitors for server PING checks. When a PING is received it sends the PONG needed to stay connected. IRC commands to try: HELP, TIME, MOTD, JOIN and PRIVMSG The "/" in front of IRC commands are not needed, e.g. type JOIN #mygroup Learn about expect: http://tldp.org/LDP/LGNET/issue48/fisher.html The sample output shows snippets from an actual IRC session. Please click UP button if you like it! Show Sample Output


    9
    nik=clf$RANDOM;sr=irc.efnet.org;expect -c "set timeout -1;spawn nc $sr 6666;set send_human {.1 .2 1 .2 1};expect AUTH*\n ;send -h \"user $nik * * :$nik commandlinefu\nnick $nik\n\"; interact -o -re (PING.:)(.*\$) {send \"PONG :\$interact_out(2,string)\"}"
    omap7777 · 2015-03-18 09:10:28 46

What's this?

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.

Share Your Commands


Check These Out

Transfer SSH public key to another machine in one step
This command sequence allows simple setup of (gasp!) password-less SSH logins. Be careful, as if you already have an SSH keypair in your ~/.ssh directory on the local machine, there is a possibility ssh-keygen may overwrite them. ssh-copy-id copies the public key to the remote host and appends it to the remote account's ~/.ssh/authorized_keys file. When trying ssh, if you used no passphrase for your key, the remote shell appears soon after invoking ssh user@host.

Write comments to your history.
A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.

Read aloud a text file in Mac OS X

Get Hardware UUID in Mac OS X
Formats the output from `ioreg` into XML, then parses the XML with `xmllint`'s xpath feature.

Tracklist reaplace backspace to '-'
Requires perl 5.14 or greater

Download all PDFs from an authenificated website
Replace *** with the appropiate values

Multi-thread any command
For instance: $ find . -type f -name '*.wav' -print0 |xargs -0 -P 3 -n 1 flac -V8 will encode all .wav files into FLAC in parallel. Explanation of xargs flags: -P [max-procs]: Max number of invocations to run at once. Set to 0 to run all at once [potentially dangerous re: excessive RAM usage]. -n [max-args]: Max number of arguments from the list to send to each invocation. -0: Stdin is a null-terminated list. I use xargs to build parallel-processing frameworks into my scripts like the one here: http://pastebin.com/1GvcifYa

disable caps lock
a quick one-line way to disable caps lock while running X.

Image to color palette generator
Extract a color palette from a image useful for designers. Example usage: $extract-palette myawesomeimage.jpg 4 Where the first argument is the image you want to extract a palette from. The second argument is the number of colors you want. It may be the case where you want to change the search space. In that case, change the -resize argument to a bigger or smaller result. See the ImageMagick documentation for the -resize argument.

Setting reserved blocks percentage to 1%
According to tune2fs manual, reserved blocks are designed to keep your system from failing when you run out of space. Its reserves space for privileged processes such as daemons (like syslogd, for ex.) and other root level processes; also the reserved space can prevent the filesystem from fragmenting as it fills up. By default this is 5% regardless of the size of the partition. http://www.ducea.com/2008/03/04/ext3-reserved-blocks-percentage/


Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: