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May 19, 2015 - A Look At The New Commandlinefu
I've put together a short writeup on what kind of newness you can expect from the next iteration of clfu. Check it out here.
March 2, 2015 - New Management
I'm Jon, I'll be maintaining and improving clfu. Thanks to David for building such a great resource!

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Psst. Open beta.

Wow, didn't really expect you to read this far down. The latest iteration of the site is in open beta. It's a gentle open beta-- not in prime-time just yet. It's being hosted over at UpGuard (link) and you are more than welcome to give it a shot. Couple things:

  • » The open beta is running a copy of the database that will not carry over to the final version. Don't post anything you don't mind losing.
  • » If you wish to use your user account, you will probably need to reset your password.
Your feedback is appreciated via the form on the beta page. Thanks! -Jon & CLFU Team

Commands tagged printf from sorted by
Terminal - Commands tagged printf - 29 results
[email protected]' ; expect -c "log_user 0 ; set timeout -1 ; spawn usbmon -i usb0 ; expect -re \"C.*Ii.*-2:128\" { spawn sendmail $mysms ; send \"Smart Home Sensor Triggered\n.\n\" ; expect }"

An old USB A/B cable is all you need to make your own Smart Home hardware!

Cut off and discard the B-portion of the USB cable. On the A side, connect the RED (+) and WHITE (D-) wires via a 1 kiloohm resistor.



Now plug the cable into a USB port on your Linux computer. Your hardware is ready!

Run the above command after changing variable mysms to your personal email-to-SMS gateway info as required by your cellular service provider.

The command uses the amazing usbmon tool (see link below) to detect the cable.

For the curious, to view the raw usbmon output, run this command: (Also see the sample output)

usbmon -i usb0

How does it work? When the red and white wires are connected (via the 1 kiloohm resistor) the USB hardwere is tricked into thinking that a new USB device is trying to start up.

We then use the usbmon utility to capture the host USB events as it tries to talk to the cable.

The expect utility watches the usbmon stream and waits for the disconnect text "-2:128" before sending the SMS message.

Finally, the sendmail tool is used to email the SMS message to your smartphone via your cellular provider's SMS-to-email gateway.

As a result, when the electrical connection between the red and white wire is interrupted, or the USB cable is unplugged from your computer, you get an SMS notification of the disconnect event on your smartphone.

Could this be the cheapest smart home gadget ever? What are YOU going to sense with it?

Please let me know in the comments and please don't forget to click it up!





printf "%s\t%s\t%s\n" {1..9} '*' 0 '#'
2014-12-27 11:27:24
User: flatcap
Functions: printf
Tags: printf

Draw a telephone keyboard, using just a shell built-in command.

find . -printf '%.5m %10M %#9u %-9g %TY-%Tm-%Td+%Tr [%Y] %s %p\n'|sort -nrk8|head
printf -- " -e %s" ${ARRAY[*]}
2014-02-25 03:34:12
User: SEJeff
Functions: printf

[[email protected] container] (master)$ echo docker run $(printf -- " -e %s" ${DOCKER_APP_VARS[*]}) -name 12factorapp mattdm/fedora-small

docker run -e DATABASE_USER=dbuserro, -e DATABASE_PASSWORD=maipass -name 12factorapp mattdm/fedora-small

Note that the printf method by itsself doesn't include a newline (\n), so you'll need to embed it into an echo statement or something that does.

function brainwallet_checksum () { (o='openssl sha256 -binary'; p='printf';($p %b "\x80";$p %s "$1"|$o)|$o|sha256sum|cut -b1-8); }

A bitcoin "brainwallet" is a secret passphrase you carry in your brain.

The Bitcoin Brainwallet Exponent Calculator is the second of three functions needed to calculate a bitcoin PRIVATE key. Roughly, checksum is the first 8 hex digits of sha256(sha256(0x80+sha256(passphrase)))

Note that this is a bash function, which means you have to type its name to invoke it

function brainwallet_exponent () { printf %s "$1"|sha256sum|head -c 64; }
2014-02-18 01:49:09
User: nixnax
Functions: head printf

A bitcoin "brainwallet" is a secret passphrase you carry in your brain.

The Bitcoin Brainwallet Exponent Calculator is one of three functions needed to calculate the bitcoin PRIVATE key. Roughly, the formula is exponent = sha256 (passphrase)

Note that this is a bash function, which means you have to type its name to invoke it.

You can check the accuracy of the results here http://brainwallet.org

echo -e "CHECK=SAMPLE" output --command_to_long
2013-04-03 08:46:47
User: techie
Functions: echo

This is longer than others on here. The reason for this is I have combined two different matrix commands so it would work on all computers. I logged onto my server through a computer and it worked fine. I logged into my server through a mac and it looked $4!t so I have made one that works through both.

alias LS='find -mount -maxdepth 1 -printf "%.5m %10M %#9u:%-9g %#5U:%-5G %TF_%TR %CF_%CR %AF_%AR %#15s [%Y] %p\n" 2>/dev/null'
2013-02-06 17:54:14
User: AskApache
Functions: alias

This alias is super-handy for me because it quickly shows the details of each file in the current directory. The output is nice because it is sortable, allowing you to expand this basic example to do something amazing like showing you a list of the newest files, the largest files, files with bad perms, etc..

A recursive alias would be:

alias LSR='find -mount -printf "%.5m %10M %#9u:%-9g %#5U:%-5G %TF_%TR %CF_%CR %AF_%AR %#15s [%Y] %p\n" 2>/dev/null'

From: http://www.askapache.com/linux/bash_profile-functions-advanced-shell.html

testt(){ o=abcdefghLkprsStuwxOGN;echo $@;for((i=0;i<${#o};i++));do c=${o:$i:1};test -$c $1 && help test | sed "/^ *-$c/!d;1q;s/^[^T]*/-$c /;s/ if/ -/";done; }
2012-02-21 16:54:53
User: AskApache
Functions: echo sed test

Applies each file operator using the built-in test.

testt /home/askapache/.sq


-a True - file exists.

-d True - file is a directory.

-e True - file exists.

-r True - file is readable by you.

-s True - file exists and is not empty.

-w True - the file is writable by you.

-x True - the file is executable by you.

-O True - the file is effectively owned by you.

-G True - the file is effectively owned by your group.

-N True - the file has been modified since it was last read.

Full Function:

testt ()


local dp;

until [ -z "${1:-}" ]; do


[[ ! -a "$1" ]] && dp="$PWD/$dp";

command ls -w $((${COLUMNS:-80}-20)) -lA --color=tty -d "$dp";

[[ -d "$dp" ]] && find "$dp" -mount -depth -wholename "$dp" -printf '%.5m %10M %#15s %#9u %-9g %#5U %-5G %Am/%Ad/%AY %Cm/%Cd/%CY %Tm/%Td/%TY [%Y] %p\n' -a -quit 2> /dev/null;

for f in a b c d e f g h L k p r s S t u w x O G N;


test -$f "$dp" && help test | sed "/-$f F/!d" | sed -e 's#^[\t ]*-\([a-zA-Z]\{1\}\) F[A-Z]*[\t ]* True if#-\1 "'$dp'" #g';





ls -d $PWD/*
printf "$PWD/%s\n" *
2011-12-16 13:43:01
User: flatcap
Functions: printf
Tags: printf

List the full path of some files.

You can add ".*" on the end if you want to display hidden files.

myhex=$(printf '%02X' ${myip//./ };)
2011-11-30 15:12:28
Functions: printf
Tags: IP hex printf octet

Converts IP octets to hex using printf command. Useful for generating pxeboot aliases in the pxelinux.cfg folder.

MIN=10;for ((i=MIN*60;i>=0;i--));do echo -ne "\r$(date -d"0+$i sec" +%H:%M:%S)";sleep 1;done
2011-02-20 11:56:28
User: flatcap
Functions: echo sleep

Countdown clock - Counts down from $MIN minutes to zero.

I let the date command do the maths.

This version doesn't use seq.

println() {echo -n -e "\e[038;05;${2:-255}m";printf "%$(tput cols)s"|sed "s/ /${1:-=}/g"}
2011-01-09 18:08:18
User: joedhon
Functions: printf sed
Tags: sed tput printf

function for .bash_aliases that prints a line of the character of your choice in the color of your choice across the terminal.

Default character is "=", default color is white.

tail -f file |xargs -IX printf "$(date -u)\t%s\n" X
echo "10 i 2 o $(date +"%H%M"|cut -b 1,2,3,4 --output-delimiter=' ') f"|dc|tac|xargs printf "%04d\n"|tr "01" ".*"
2010-11-24 23:49:21
User: unefunge
Functions: echo printf tr xargs

displays current time in "binary clock" format

(loosely) inspired by: http://www.thinkgeek.com/homeoffice/lights/59e0/



.... - 1st hour digit: 0

*..* - 2nd hour digit: 9 (8+1)

.*.. - 1st minutes digit: 4

*..* - 2nd minutes digit: 9 (8+1)

Prompt-command version:

PROMPT_COMMAND='echo "10 i 2 o $(date +"%H%M"|cut -b 1,2,3,4 --output-delimiter=" ") f"|dc|tac|xargs printf "%04d\n"|tr "01" ".*"'

PROMPT_COMMAND='seq $COLUMNS | xargs -IX printf "%Xs\r" @'
for i in ???.jpg; do mv $i $(printf %04d $(basename $i .jpg) ).jpg ; done
2010-11-18 23:48:41
User: carlesso
Functions: basename mv printf
Tags: rename cp printf

Useful if you have a list of images called 1 2 3 4 and so on, you can adapt it to rewrite it as 4 (in this example) 0-padded number.

( x=`tput op` y=`printf %$((${COLUMNS}-6))s`;for i in {0..256};do o=00$i;echo -e ${o:${#o}-3:3} `tput setaf $i;tput setab $i`${y// /=}$x;done; )

This is super fast and an easy way to test your terminal for 256 color support. Unlike alot of info about changing colors in the terminal, this uses the ncurses termcap/terminfo database to determine the escape codes used to generate the colors for a specific TERM. That means you can switch your terminal and then run this to check the real output.

tset xterm-256color

at any rate that is some super lean code!

Here it is in function form to stick in your .bash_profile

aa_256 ()


( x=`tput op` y=`printf %$((${COLUMNS}-6))s`;

for i in {0..256};



echo -e ${o:${#o}-3:3} `tput setaf $i;tput setab $i`${y// /=}$x;

done )


From my bash_profile: http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

L(){ l=`builtin printf %${2:-$COLUMNS}s` && echo -e "${l// /${1:-=}}"; }

One of the first functions programmers learn is how to print a line. This is my 100% bash builtin function to do it, which makes it as optimal as a function can be. The COLUMNS environment variable is also set by bash (including bash resetting its value when you resize your term) so its very efficient. I like pretty-output in my shells and have experimented with several ways to output a line the width of the screen using a minimal amount of code. This is like version 9,000 lol.

This function is what I use, though when using colors or other terminal features I create separate functions that call this one, since this is the lowest level type of function. It might be better named printl(), but since I use it so much it's more optimal to have the name contain less chars (both for my programming and for the internal workings).

If you do use terminal escapes this will reset to default.

tput sgr0

For implementation ideas, check my


find $PWD -maxdepth 1 -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n'

I love this function because it tells me everything I want to know about files, more than stat, more than ls. It's very useful and infinitely expandable.

find $PWD -maxdepth 1 -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n' | sort -rgbS 50%

00761 drwxrw---x askapache:askapache 777:666 [06/10/10 | 06/10/10 | 06/10/10] [d] /web/cg/tmp

The key is:

# -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n'

which believe it or not took me hundreds of tweaking before I was happy with the output.

You can easily use this within a function to do whatever you want.. This simple function works recursively if you call it with -r as an argument, and sorts by file permissions.

lsl(){ O="-maxdepth 1";sed -n '/-r/!Q1'<<<$@ &&O=;find $PWD $O -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n'|sort -rgbS 50%; }

Personally I'm using this function because:

lll () { local a KS="1 -r -g"; sed -n '/-sort=/!Q1' <<< $@ && KS=`sed 's/.*-sort=\(.*\)/\1/g'<<<$@`; find $PWD -maxdepth 1 -printf '%.5m %10M %#9u:%-9g %#5U:%-5G [%AD | %TD | %CD] [%Y] %p\n'|sort -k$KS -bS 50%; }

# i can sort by user

lll -sort=3

# or sort by group reversed

lll -sort=4 -r

# and sort by modification time

lll -sort=6

If anyone wants to help me make this function handle multiple dirs/files like ls, go for it and I would appreciate it.. Something very minimal would be awesome.. maybe like:

for a; do lll $a; done

Note this uses the latest version of GNU find built from source, easy to build from gnu ftp tarball. Taken from my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

sortwc () { local L;while read -r L;do builtin printf "${#L}@%s\n" "$L";done|sort -n|sed -u 's/^[^@]*@//'; }
2010-05-20 20:13:52
User: AskApache
Functions: printf read sed sort

This provides a way to sort output based on the length of the line, so that shorter lines appear before longer lines. It's an addon to the sort that I've wanted for years, sometimes it's very useful. Taken from my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html

printf "\n%25s%10sTOTAL\n" 'FILE TYPE' ' '; for ext in $(find . -iname \*.* | egrep -o '\.[^[:space:].]+$' | egrep -v '\.svn*' | sort -f | uniq -i); do count=$(find . -iname \*$ext | wc -l); printf "%25s%10s%d\n" $ext ' ' $count; done
2010-04-16 21:12:11
User: rkulla
Functions: egrep find printf sort uniq wc

I created this command to give me a quick overview of how many file types a directory, and all its subdirectories, contains. It works based off file extension, rather than file(1)'s magic output, because it ended up being more accurate and less confusing.

Files that don't have an ext (README) are generally not important for me to want to count, but you're free to customize this fit your needs.

jot -b '#' -s '' $COLUMNS
2010-04-13 22:03:39
User: dennisw
Tags: tr tput printf

For BSD-based systems, including OS X, that don't have seq.

This version provides a default using tput in case $COLUMNS is not set:

jot -b '#' -s '' ${COLUMNS:-$(tput cols)}
printf -v row "%${COLUMNS}s"; echo ${row// /#}
2010-04-13 21:56:46
User: dennisw
Functions: echo printf
Tags: tr tput printf

Pure Bash

This will print a row of characters the width of the screen without using any external executables. In some cases, COLUMNS may not be set. Here is an alternative that uses tput to generate a default if that's the case. And it still avoids using tr.

printf -v row "%${COLUMNS:-$(tput cols)}s"; echo ${row// /#}

The only disadvantage to either one is that they create a variable.