Commands by unixmonkey365 (6)

  • I wasted two hours reading the sox documentation and searching on the web for the format of some obscure fscking sound sample, and then finally came up with this. This plays only the first three seconds of your unknown formatted sound file using every one of sox's built-in filetypes. If you don't get an exact match, you may get close. . I could not fit every single type in and keep it under 127 characters, so you will have to replace "..." with the full list obtainable by `$ sox --help` (or try `Show sample output`) . note: /usr/bin/play should be linked to sox on most systems. Show Sample Output


    1
    for x in 8svx aif aifc aiff aiffc ... wv wve xa xi ; do echo $x ; play -q -t $x soundfile trim 0 3 ; done
    unixmonkey365 · 2011-12-09 00:23:45 8
  • This is just a phrase I use to help me remember which way is what when using nice (top, renice, etc.), and not a command, (unless you really want this in your .bash_history to help remind you.) I was using the command `man nice ` way too much just to look up which way is what. This saves 9 keystrokes every time I remember it. Make sure you downvote me if you think mnemonics sux. Otherwise I hope this helps someone else.


    1
    # Negative is Not Nice
    unixmonkey365 · 2011-11-29 19:05:23 7
  • Someone over at Mozilla dot Org probably said, "I know, let's create a super-duper universal replacement for browser cookies that are persistent and even more creepy and then NOT give our browser users the tools they need to monitor, read, block or selectively remove them!" . This will let you see all the DOM object users in all your firefox profiles. Feel free to toss a `| sort -u` on the end to remove dupes. . I highly recommend you treat these as "session cookies" by scripting something that deletes this sqlite database during each firefox start-up. . note: does not do anything for so-called "flash cookies" Show Sample Output


    8
    strings ~/.mozilla/firefox/*/webappsstore.sqlite|grep -Eo "^.+\.:" |rev
    unixmonkey365 · 2011-09-26 15:23:09 11
  • Another function to stick into your .bashrc This spits out the time two minutes in the future, but already formatted for pasting into your crontab file for testing without any thought required on your part. Frequently things don't work the way you expect inside a crontab job, and you probably want to find out now that your $PATH is completely different inside of cron or other global variables aren't defined. So this will generate a date you can use for testing now, and then later you can change it to run at 5:37 am on a Sunday evening. Show Sample Output


    7
    crontest () { date '-d +2 minutes' +'%M %k %d %m *'; }
    unixmonkey365 · 2011-09-16 00:47:24 6
  • cn stands for "Cat Null" . The idea is that sometimes you run across something on maybe a webpage - like commandlinefu - that you want to try out on your terminal. You could put a '#' in and then paste it, but what if it is several lines? . This command will echo the pasted characters to the screen and divert them to the bit bucket. . Put this simple alias in your .bashrc, hit cn, paste away, and hit a ctrl+c or a ctrl+d when you are done to get your prompt back. Show Sample Output


    -3
    alias cn='cat > /dev/null'
    unixmonkey365 · 2011-09-16 00:00:28 8
  • Evoke from the command like as: timeDNS commandlinefu.com . This isn't too terribly practical, but it is a good code example of using subshells to run the queries in parallel and the use of an "anonymous function" (a/k/a "inline group") to group i/o. . I'm assuming you have already defined your local DNS cache as ${local_DNS}, (here, it's 192.168.0.1). . You do need to install `moreutils` to get `sponge`. . If you're willing to wait, a slower version w/o sponge, (and w/o sorting), is this: . DNS () { for x in "192.168.0.1" "208.67.222.222" "208.67.220.220" "198.153.192.1" "198.153.194.1" "156.154.70.1" "156.154.71.1" "8.8.8.8" "8.8.4.4"; do (echo -n "$x "; dig @"$x" "$*"|grep Query) ; done ; } Show Sample Output


    1
    timeDNS () { { for x in "${local_DNS}" "208.67.222.222" "208.67.220.220" "198.153.192.1" "198.153.194.1" "156.154.70.1" "156.154.71.1" "8.8.8.8" "8.8.4.4"; do ({ echo -n "$x "; dig @"$x" "$*"|grep Query ; }|sponge &) done ; } | sort -n -k5 ; }
    unixmonkey365 · 2011-08-18 01:11:53 7

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ttyS0 - terminal on serial connection
I actually planned to do this for quite a long time, but since I haven't had any suitable client hardware, I procrastinated this. Now, the old laptop I've got from my dad, features an RS-232 port. So, now that I had technically a client, that I could test my RS-232 connection with, I ordered a null modem cable. There is no RS-232 outlet on my desktop computer directly on the mainboard, but theres a connector on the mainbord, where a RS-232 outlet can be attached to. The outlet will then cover up a PCI slot. # Activating RS-232 Ok, once all cables were in place, I tried to access both RS-232 ports by reading from them directly. They're usually ttyS0 or ttyS1, depending what COM-Port it is. From the file /proc/tty/driver/serial, information about the serial setup can be obtained. A setserial -q /dev/ttyS0 might be usefull as well. Usually, the UART Type is 16550A, on a standard PC. Mine wasn't working though. At leas not right from the start, when I tried to read the interface with cat /dev/ttyS0 I got the following error: # cat /dev/ttyS0 cat: /dev/ttyS0: Input/output error Obviously, the driver couldn't activate the hardware. Reason was, it was deactivated in BIOS. After activating RS-232 there, it worked well. As a last action, I added myself to the uucp group, so I have user permission to the serial lines. It is not necessary for the terminal setup, but a good idea to do so, just for future projects, maybe... # Setting up a terminal Once the Serial line is configured and working properly, it's time to let a terminal run on that port. This is what I added to my /etc/inittab : s0:2345:respawn:/sbin/agetty -L 38400 ttyS0 I added it quite on the top of that file, right below the 'si' statement, mingetty cannot be used for serial connections, it cannot be run in a console, too. I tried it for testing purposes, but the cosole - along with your login program - will log you out, as soon as you log in over your serial line. '-L' means this is a local line, with no carrier signal. 38400 is the standard speed of a Linux console, it might be a bit high, I was told, but it works well. I tested that with some higher values as well (115200) and it worked too, I guess it tepends on things like cable length, etc. Last parameter, is the serial tty to listen on. The terminal type can be specified as an additional parameter at the end of the parameter list, vt102, for instance. This is sometimes required, depending on the client. After finishing editing /etc/inittab, an init q will make the system re-read /etc/inittab and apply changes. The agetty should now be listening on ttyS0. #Setting up a client It's time to establish a connection and test the serial line. I use a laptop, that has an RS-232 port, so some preliminary setup is required. I tried minicom as terminal initially, but it turned out, not to be the best client. It initializes the modem, this lasts quite long, and it doesn't convey ANSI colors. So the better option is cu, it's part of the UUCP-Package. Oh, and the serial port of that computer, has to be accessible as well, of course. Once everything was set up, I established the connection: $ cu -l ttyS0 -38400 --nostop Pretty self explanatory, I think. The --nostop option disables XON/XOFF handling. # root access over ttyS0 In order to become root over the serial terminal, the tty needs to be added to /etc/securetty I appended ttyS0 to the end of the file. It is now possible, to gain root access over the serial terminal. The agetty process needs to be restarted to apply changes. # Accessing GRUB over ttyS0 To make bootloader access possible over ttyS0, some changes to /boot/grub/menu.lst need to be done. (GRUB is the bootloader I use, I suppose LiLo has similar capabilities.) Those are the lines, I appended to the top of my menu.lst : serial --unit=0 --speed=38400 --word=8 --parity=no --stop=1 terminal --timeout=3 serial console The serial command initiates the serial terminal option, --unit=0 defines our first serial connector, I my case, it's the only one I have on my machine. I used the standard Linux-Console speed, as well as the "8N1" connection strategy. terminal defines the terminal priorities, first terminal (serial) is the standard one, the last one is the secondary terminal (console). --timeout=3 enables a delay on both consoles, with a prompt for a keystroke. Depending on which terminal, the key is pressed, this terminal, will be used. If no key is pressed after the timeout, the standard console (in my case serial) will be used. # Relaying Kernel output on boot The Kernel accepts multiple console options, of which the last one, is the standard console, and the one that will be used in Single User mode. These are my Kernel options: title Fedora Core (2.6.20-1.2316.fc5) root (hd0,0) kernel /vmlinuz-2.6.20-1.2316.fc5 ro root=/dev/VolGroup00/LogVol00 rhgb quiet vga=795 console=tty0 console=ttyS0,38400 initrd /initrd-2.6.20-1.2316.fc5.img console=tty0 is the standard console, located on the machine, i.e. monitor and keyboard.

Ergo browsing 'pacman' queries (Arch)
Alternative1 (grep support): pacman -Ss python | paste - - | grep --color=always -e '/python' | less -R Alternative2 (eye-candy, no grep): pacman --color=always -Ss "python" | paste - - | less -R in ~/.bashrc: pkg-grep() { pacman -Ss "$1" | paste - - | grep --color=always -e "${2:-$1}" | less -R ; } pkg-search() { pacman --color=always -Ss "python" | paste - - | less -R; }

List open TCP/UDP ports

permanently let grep colorize its output
This will create a permanent alias to colorize the search pattern in your grep output

no more line wrapping in your terminal
works on all unices.

remove audio trac from a video file
create a copy of a video file without the audio tracs


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