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 0
  • 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 4

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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

Get your outgoing IP address

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Copy the sound content of a video to an mp3 file
-vn removes tha video content, the copy option tells ffmpeg to use the same codec for generating the output

Keep track of diff progress
You're running a program that reads LOTS of files and takes a long time. But it doesn't tell you about its progress. First, run a command in the background, e.g. $ find /usr/share/doc -type f -exec cat {} + > output_file.txt Then run the watch command. "watch -d" highlights the changes as they happen In bash: $! is the process id (pid) of the last command run in the background. You can change this to $(pidof my_command) to watch something in particular.

Print a row of characters across the terminal
shorter than alternative

Use top to monitor only all processes with the same name fragment 'foo'
top accecpts a comma separated list of PIDs.

Notepad in a browser
A commandline version of the notepad in a browser: http://www.commandlinefu.com/commands/view/12161/notepad-in-a-browser-type-this-in-the-url-bar All credit to the origional author of this fantastic command, whos only failing as most of the comments pointed out was that it wasn't a command... well, now its a command. Send all upvotes to dtlp747.

Add page numbers to a PDF
Put this code in a bash script. The script expects the PDF file as its only parameter. It will add a header to the PDF containing the page numbers and output it to a file with the suffix "-header.pdf" Requires enscript, ps2pdf and pdftk.

Ping all hosts on 192.168.1.0/24


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