Commands tagged cellular automata 2D (1)

  • xmas lights for your terminal - switching the $l value to something like 1200 and zooming out on your terminal gives a great view ... Show Sample Output

    perl -le '$l=80;$l2="!" x $l;substr+($l2^=$l2),$l/2,1,"\xFF";{local $_=$l2;y/\0\xFF/ ^/;print;($lf,$rt)=map{substr $l2 x 2,$_%$l,$l;}1,-1;$l2=$lf^$rt;select undef,undef,undef,.1;redo}'
    l3v3l · 2013-06-21 06:00:24 0

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Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Download Apple movie trailers
Copy the link to an HD movie trailer in to this command. It's more eleganant if it's put in a to a script, taking the URL as input.

(Debian/Ubuntu) Discover what package a file belongs to
Works similar to dpkg -S, but uses the locatedb and is thus inarguably a lot faster - if the locatedb is current.

clear screen, keep prompt at eye-level (faster than clear(1), tput cl, etc.)
this leaves the cursor at the bottom of the terminal screen, where your eyes are. ctrl-l moves it to the top, forcing you to look up.

Delete line number 10 from file
Very useful when the ssh key of a host has changed and ssh refuses to connect to the machine, while giving you the line number that has changed in ~/.ssh/known_hosts.

Pass TAB as field separator to sort, join, cut, etc.
Use this BASH trick to create a variable containing the TAB character and pass it as the argument to sort, join, cut and other commands which don't understand the \t notation. $ sort -t $'\t' ... $ join -t $'\t' ... $ cut -d $'\t' ...

Remove all .svn folders

Remove security limitations from PDF documents using ghostscript (for Windows)
#4345 also works under windows

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

List files by quoting or escaping special characters.
Tested and works on Linux.

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