Commands tagged array (8)

  • If you should happen to find yourself needing some binary numbers, this is a quickie way of doing it. If you need more digits, just add more "{0..1}" sequences for each digit you need. You can assign them to an array, too, and access them by their decimal equivalent for a quickie binary to decimal conversion (for larger values it's probably better to use another method). Note: this works in bash, ksh and zsh. For zsh, though, you'll need to issue a setopt KSH_ARRAYS to make the array zero-based. binary=({0..1}{0..1}{0..1}{0..1}) echo ${binary[9]} Show Sample Output


    18
    echo {0..1}{0..1}{0..1}{0..1}
    dennisw · 2009-06-23 17:30:20 8

  • 10
    read -a ARR <<<'world domination now!'; echo ${ARR[2]};
    unefunge · 2010-12-03 16:27:03 4
  • Convert some decimal numbers to binary numbers. You could also build a general base-converter: function convBase { echo "ibase=$1; obase=$2; $3" | bc; } then you could write function decToBun { convBase 10 2 $1; } Show Sample Output


    4
    function decToBin { echo "ibase=10; obase=2; $1" | bc; }
    woxidu · 2009-11-24 22:57:58 2
  • Like 7171, but fixed typo, uses fewer variables, and even more cryptic! Show Sample Output


    4
    read -a A<<<".*.**..*....*** 8 9 5 10 6 0 2 11 7 4";for C in `date +"%H%M"|fold -w1`;do echo "${A:${A[C+1]}:4}";done
    __ · 2010-12-02 22:04:49 3
  • This type of join is clearly documented in the bash manual. Only the first character of IFS is used for the delimiter. Show Sample Output


    4
    (IFS=,; echo "${array[*]}")
    aspiers · 2013-09-25 10:36:38 6
  • cryptic version Show Sample Output


    2
    read -a A <<<"8 9 5 10 6 0 3 11 7 4";B='.*.**..*....***';for C in $(date +"%H%M"|fold -w1);do echo "${B:${A[C]}:4}";done
    unefunge · 2010-11-26 11:29:23 3
  • I was looking for the fastest way to create a bunch of ansi escapes for use in echo -e commands throughout a lot of my shell scripts. This is what I came up with, and I actually stick that loop command in a function and then just call that at the beginning of my scripts to not clutter the environment with these escape codes, which can wreck havok on my terminal when I'm dumping the environment. More of a cool way to store escape ansi codes in an array. You can echo them like: echo -e "${CC[15]}This text is black on bright green background." I usually just use with a function: # setup_colors - Adds colors to array CC for global use # 30 - Black, 31 - Red, 32 - Green, 33 - Yellow, 34 - Blue, 35 - Magenta, 36 - Blue/Green, 37 - White, 30/42 - Black on Green '30\;42' function setup_colors(){ declare -ax CC; for i in `seq 0 7`;do ii=$(($i+7));CC[$i]="\033[1;3${i}m";CC[$ii]="\033[0;3${i}m";done;CC[15]="\033[30;42m"; export R='\033[0;00m';export X="\033[1;37m"; }; export -f setup_colors CC[15] has a background of bright green which is why it is separate. R resets everything, and X is my default font of bright white. CC[15]="\033[30;42m"; R=$'\033[0;00m'; X=$'\033[1;37m' Those are just my favorite colors that I often use in my scripts. You can test which colors by running for i in $(seq 0 $((${#CC[@]} - 1))); do echo -e "${CC[$i]}[$i]\n$R"; done See: http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html for more usage. Show Sample Output


    1
    declare -ax CC; for i in `seq 0 7`;do ii=$(($i+7)); CC[$i]="\033[1;3${i}m"; CC[$ii]="\033[0;3${i}m"; done
    AskApache · 2009-09-21 07:00:55 7
  • Ever need to get some text that is a specific number of characters long? Use this function to easily generate it! Doesn't look pretty, but sure does work for testing purposes! Show Sample Output


    0
    genRandomText() { a=( a b c d e f g h i j k l m n o p q r s t u v w x y z );f=0;for i in $(seq 1 $(($1-1))); do r=$(($RANDOM%26)); if [ "$f" -eq 1 -a $(($r%$i)) -eq 0 ]; then echo -n " ";f=0;continue; else f=1;fi;echo -n ${a[$r]};done;echo"";}
    bbbco · 2012-01-20 21:18:16 2

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

check open ports without netstat or lsof

Convert a videos audio track to ogg vorbis.
Assumes you have ffmpeg and oggenc. Similar to other scripts here, but this time outputting to Ogg Vorbis. I added the variable assignment for a nice output name. This is part of an interactive bash script I have with a few little multimedia tasks in it. http://www.dward.us/software/VSAK.sh

Monitoring file handles used by a particular process
-r : repeat mode

Rename all images in current directory to filename based on year, month, day and time based on exif information

How to extract 5000 records from each table in MySQL
How to extract data from one table: mysqldump --opt --where="true LIMIT 5000" dbinproduzione tabella > miodbditest_tabella.sql

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

prettier "cal" command
Displays the same output as "cal", but with the current day highlighted (probably dependent on gnu grep, as I'm not sure other grep's support the "--color=auto" option). Tested and working on Ubuntu 11 and OSX Lion.

Get the Volume labels all bitlocker volumes had before being encrypted
Get information of volume labels of bitlocker volumes, even if they are encrypted and locked (no access to filesystem, no password provided). Note that the volume labels can have spaces, but only if you name then before encryption. Renaming a bitlocker partition after being encrypted does not have the same effect as doing it before.

Perform sed substitution on all but the last line of input
In this simple example the command will add a comma to the end of every line except the last. I found this really useful when programatically constructing sql scripts. See sample output for example.

Show the command line of a process that use a specific port (ubuntu)


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: