Commands by greggster (7)

  • Use vim's diff mode to edit two or more files in one window. The '+diffoff!' turns off diff highlighting when the session is started. Use ctrl+w + ctrl+w to switch between windows. Show Sample Output


    2
    vim -d '+diffoff!' file1 file2
    greggster · 2012-08-30 07:51:41 0
  • Sort lines within vi editor. In this example sort lines 33-61 and lines 4-9 asciibetically. Show Sample Output


    6
    :33,61 !sort
    greggster · 2011-05-06 06:10:05 1
  • rm -rf .* matches ".." and thus one goes up a level and wipes out more than intended. In bash, .??* safely accomplishes what one intends - remove those .files The ? matches most characters except "/", thus .?? does not match ../ and so one is safe. Show Sample Output


    0
    rm -rf .??*
    greggster · 2011-03-11 07:21:58 5
  • When setting up a new aliases file, or having creating a new file.. About every time after editing an aliases file, I source it. This alias makes editing alias a bit easier and they are useful right away. Note if the source failed, it will not echo "aliases sourced". Sub in vi for your favorite editor, or alter for ksh, sh, etc.


    7
    alias va='vi ~/.aliases; source ~/.aliases && echo "aliases sourced"'
    greggster · 2011-03-10 06:41:37 1
  • This is for bash - make an alias - also a good blueprint for making aliases that take arguments to functions. If for Solaris use "-size +${1}000000c" to replace "-size +${1}M" Show Sample Output


    0
    alias big='BIG () { find . -size +${1}M -ls; }; BIG $1'
    greggster · 2011-03-10 06:33:00 1
  • until (ssh root@10.1.1.39 2> /dev/null); do date; sleep 15; done In this case will execute "date" then "sleep 15" until we are able to ssh into server, such as after a reboot Could also be like: until ( ping 10.1.1.39 1> /dev/null); do echo "server 10.1.1.39 is down"; sleep 15; done Show Sample Output


    8
    until (ssh root@10.1.1.39 2> /dev/null); do date; sleep 15; done
    greggster · 2011-03-08 08:42:12 2
  • This is useful for quickly jumping around branches in a file system, or operating on a parellel file. This is tested in bash. cd to (substitute in PWD, a for b) where PWD is the bash environmental variable for the "working directory" Show Sample Output


    7
    cd ${PWD/a/b}
    greggster · 2011-03-03 06:27:12 6

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Selecting a random file/folder of a folder
Also looks in subfolders

Kill all processes that don't belong to root/force logoff
explanation: grep -- displays process ids -v -- negates the matching, displays all but what is specified in the other options -u -- specifies the user to display, or in this case negate The process loops through all PIDs that are found by pgrep, then orders a forced kill to the processes in numerical order, effectively killing the parent processes first including the shells in use which will force the users to logout. Tested on Slackware Linux 12.2 and Slackware-current

Create a transition between two videos
We take the first 50 frames of a.mp4 for track a, and 24 blank frames followed by b.mp4 for track b. We then create a transition from track a to track b starting from frame 25 and ending at frame 49. The output is stored in out.mp4 To view the results without saving remove "-consumer avformat:out.mp4" from the end. Documentation of the mlt framework and the melt command can be found here: http://www.mltframework.org/bin/view/MLT/Documentation

Install pip with Proxy
Installs pip packages defining a proxy

List all information about all files (in current dir)
This is a funny usage of the traditional command ls. It could be basically simplified as: $ ls -a -l Duplicating arguments is permitted: $ ls -a -l -l And this markup could be shortened as: $ ls -al Extra note: To view filesizes like a pro, pray for your God: $ ls -allah

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Numeric zero padding file rename
rename file name with fixed length nomeric format pattern

Skip to next selection in playlist
Uses process signal to play next selection

Are the two lines anagrams?
This works by reading in two lines of input, turning each into a list of one-character matches that are sorted and compared.

Makes the permissions of file2 the same as file1
Also works with: $chgrp --reference file1 file2 $chown --reference file1 file2


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