Commands using printf sorted by votes

Commands using printf (211)

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April Fools' Day Prank

Add this to a fiend's .bashrc. PROMPT_COMMAND will run just before a prompt is drawn. RANDOM will be between 0 and 32768; in this case, it'll run about 1/10th of the time. \033 is the escape character. I'll call it \e for short. \e7 -- save cursor position. \e[%d;%dH -- move cursor to absolute position \e[4%dm \e[m -- draw a random color at that point \e8 -- restore position.
This is sample output - yours may be different.
25

PROMPT_COMMAND='if [ $RANDOM -le 3200 ]; then printf "\0337\033[%d;%dH\033[4%dm \033[m\0338" $((RANDOM%LINES+1)) $((RANDOM%COLUMNS+1)) $((RANDOM%8)); fi'

hotdog003 · 2010-04-01 06:52:32 18
Brute force discover

Show the number of failed tries of login per account. If the user does not exist it is marked with *. Show Sample Output
This is sample output - yours may be different.
```
$ sudo zcat /var/log/auth.log.*.gz | awk '/Failed password/&&!/for invalid user/{a[$9]++}/Failed password for invalid user/{a["*" $11]++}END{for (i in a) printf "%6s\t%s\n", a[i], i|"sort -n"}'
    33  *abc
    35  *upload
    36  *sales
    39  *center
    40  *web
    43  *fax
    43  *public
    48  *asterisk
    48  *office
    48  *temp
    53  *test
    59  *admin
    65  *info
    69  *postgres
    74  *oracle
   541  root
```
24

sudo zcat /var/log/auth.log.*.gz | awk '/Failed password/&&!/for invalid user/{a[$9]++}/Failed password for invalid user/{a["*" $11]++}END{for (i in a) printf "%6s\t%s\n", a[i], i|"sort -n"}'

point_to_null · 2009-03-21 06:41:59 17
Print diagram of user/groups

Parses /etc/group to "dot" format and pases it to "display" (imagemagick) to show a usefull diagram of users and groups (don't show empty groups).
This is sample output - yours may be different.
19

awk 'BEGIN{FS=":"; print "digraph{"}{split($4, a, ","); for (i in a) printf "\"%s\" [shape=box]\n\"%s\" -> \"%s\"\n", $1, a[i], $1}END{print "}"}' /etc/group|display

point_to_null · 2011-12-04 01:56:44 15
Print a great grey scale demo !

Seen here: http://www.pixelbeat.org/docs/terminal_colours/
This is sample output - yours may be different.
18

yes "$(seq 232 255;seq 254 -1 233)" | while read i; do printf "\x1b[48;5;${i}m\n"; sleep .01; done

frans0023 · 2009-07-03 13:58:02 9
Print a row of characters across the terminal

shorter than alternative
This is sample output - yours may be different.
17

printf "%`tput cols`s"|tr ' ' '#'

kamathln · 2010-04-05 17:12:35 9
cycle through a 256 colour palette

just for fun
This is sample output - yours may be different.
14

yes "$(seq 232 255;seq 254 -1 233)" | while read i; do printf "\x1b[48;5;${i}m\n"; sleep .01; done

pixelbeat · 2009-02-05 12:01:37 26
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.
This is sample output - yours may be different.
14

cls(){ printf "\33[2J";} or, if no printf, cat >cls;<ctrl-v><ctrl+[>[2J<enter><ctrl+d> cls(){ cat cls;}

argv · 2011-04-06 01:51:45 18
Displays the attempted user name, ip address, and time of SSH failed logins on Debian machines

A variation of a script I found on this site and then slimmed down to just use awk. It displays all users who have attempted to login to the box and failed using SSH. Pipe it to the sort command to see which usernames have the most failed logins. Show Sample Output
This is sample output - yours may be different.
```
a            210.51.0.75      Apr-14-00:45:23
admin        210.51.0.75      Apr-14-00:48:18
alexis       210.51.0.75      Apr-14-00:45:19
amal         210.51.0.75      Apr-14-00:46:18
anton        210.51.0.75      Apr-14-00:46:05
bot          210.51.0.75      Apr-14-00:45:45
```
13

awk '/sshd/ && /Failed/ {gsub(/invalid user/,""); printf "%-12s %-16s %s-%s-%s\n", $9, $11, $1, $2, $3}' /var/log/auth.log

frailotis · 2009-04-16 00:56:23 13
du with colored bar graph

A more efficient way, with reversed order to put the focus in the big ones. Show Sample Output
This is sample output - yours may be different.
```
 41.37% ############################################################## Others
 17.96% ########################### Woody Allen
 13.19% #################### Argentina
 10.86% ################ Ingmar Bergman
  6.55% ########## Serbia
  3.92% ###### NI
  2.24% ### Luis Bu?uel
  0.95% # Jean Renoir
  0.66% # M?xico
  0.64% # Colombia
  0.45% # Charlie Chaplin
  0.45% # Leni Riefenstahl
  0.42% # Cuba
  0.36% # Chile
```
12

du -x --max-depth=1|sort -rn|awk -F / -v c=$COLUMNS 'NR==1{t=$1} NR>1{r=int($1/t*c+.5); b="\033[1;31m"; for (i=0; i<r; i++) b=b"#"; printf " %5.2f%% %s\033[0m %s\n", $1/t*100, b, $2}'|tac

point_to_null · 2015-09-12 10:36:49 22
Disco lights in the terminal

Looks best in an 80x24 256-color terminal emulator.
This is sample output - yours may be different.
12

while true; do printf "\e[38;5;$(($(od -d -N 2 -A n /dev/urandom)%$(tput colors)))m.\e[0m"; done

atoponce · 2015-11-24 15:21:27 30
cycle through a 256 colour palette

Rainbow, instead of greys
This is sample output - yours may be different.
10

yes "$(seq 1 255)" | while read i; do printf "\x1b[48;5;${i}m\n"; sleep .01; done

unixmonkey4581 · 2009-09-05 04:01:23 17
Get the total length of time in hours:minutes:seconds (HH:MM:SS) of all video (or audio) in the current dir (and below)

change the *.avi to whatever you want to match, you can remove it altogether if you want to check all files.
This is sample output - yours may be different.
10

find -type f -name "*.avi" -print0 | xargs -0 mplayer -vo dummy -ao dummy -identify 2>/dev/null | perl -nle '/ID_LENGTH=([0-9\.]+)/ && ($t +=$1) && printf "%02d:%02d:%02d\n",$t/3600,$t/60%60,$t%60' | tail -n 1

grokskookum · 2009-09-24 15:50:39 34
Show bandwidth use oneliner

poorman's ifstat using just sh and awk. You must change "eth0" with your interface's name. Show Sample Output
This is sample output - yours may be different.
```
02:18:43     1.71 KiB/s in     0.11 KiB/s out
02:18:44     0.75 KiB/s in     0.25 KiB/s out
02:18:45     0.47 KiB/s in     0.20 KiB/s out
02:18:46     0.59 KiB/s in     0.15 KiB/s out
02:18:47     1.12 KiB/s in     1.37 KiB/s out
02:18:48     0.65 KiB/s in     0.21 KiB/s out
02:18:49     0.50 KiB/s in     0.31 KiB/s out
02:18:50     1.28 KiB/s in     0.37 KiB/s out
02:18:51     0.50 KiB/s in     0.05 KiB/s out
02:18:52     2.26 KiB/s in     0.10 KiB/s out
```
10

while true; do cat /proc/net/dev; sleep 1; done | awk -v dc="date \"+%T\"" '/eth0/{i = $2 - oi; o = $10 - oo; oi = $2; oo = $10; dc|getline d; close(dc); if (a++) printf "%s %8.2f KiB/s in %8.2f KiB/s out\n", d, i/1024, o/1024}'

point_to_null · 2011-11-21 05:24:44 14
A line across the entire width of the terminal

Use tput cols to find the width of the terminal and set it as the minimum field width. Show Sample Output
This is sample output - yours may be different.
```
================================
```
9

printf "%$(tput cols)s\n"|tr ' ' '='

webstandardcss · 2012-04-21 23:26:55 5
Another Matrix Style Implementation
This is sample output - yours may be different.
8

COL=$(( $(tput cols) / 2 )); clear; tput setaf 2; while :; do tput cup $((RANDOM%COL)) $((RANDOM%COL)); printf "%$((RANDOM%COL))s" $((RANDOM%2)); done

sputnick · 2009-12-15 02:48:28 12
List all available commands (bash, ksh93)
This is sample output - yours may be different.
7

printf "%s\n" ${PATH//:/\/* }

cfajohnson · 2009-11-20 22:55:59 5
reset hosed terminal
This is sample output - yours may be different.
7

cls(){ printf "\033c";} or, if no printf, cat > c ;<ctrl+v> <ctrl+[>c <enter><ctrl-d> c(){ cat c;} #usage: c

argv · 2010-08-02 07:27:22 19
convert from decimal to hexadecimal
This is sample output - yours may be different.
7

hex() { printf "%X\n" $1; }

4Aiur · 2011-12-13 04:45:21 4
urldecoding with one pure BASH builtin

You can use ordinary printf to convert "%23%21%2fbin%2fbash" into "#!/bin/bash" with no external utilities, by using a little known printf feature -- the "%b" specifier converts shell escapes. Replace % with \x and printf will understand the urlencoded string. BASH's printf has an extension to set a variable directly, too. So you get to convert urlencoded strings from garble to plaintext in one step with no externals and no backticks. Show Sample Output
This is sample output - yours may be different.
```
#!/bin/bash
```
7

VAR="%23%21%2fbin%2fbash" ; printf -v VAR "%b" "${VAR//\%/\x}" ; echo $VAR

Corona688 · 2012-01-06 22:09:01 9
Scan all open ports without any required program
This is sample output - yours may be different.
7

for i in {1..65535}; do (echo < /dev/tcp/127.0.0.1/$i) &>/dev/null && printf "\n[+] Open Port at\n: \t%d\n" "$i" || printf "."; done

emphazer · 2019-05-21 09:34:15 53
Generates a TV noise alike output in the terminal

Generates a TV noise alike output in the terminal. Can be combined with https://www.commandlinefu.com/commands/view/9728/make-some-powerful-pink-noise
This is sample output - yours may be different.
7

while true;do printf "$(awk -v c="$(tput cols)" -v s="$RANDOM" 'BEGIN{srand(s);while(--c>=0){printf("\xe2\x96\\%s",sprintf("%o",150+int(10*rand())));}}')";done

ichbins · 2020-05-08 09:55:36 346
Show the PATH, one directory per line

This is useful for examining the path. Show Sample Output
This is sample output - yours may be different.
```
/opt/local/bin
/opt/local/sbin
/usr/bin
/bin
/usr/sbin
/sbin
/usr/local/bin
/usr/X11/bin
```
6

printf ${PATH//:/\\n}

haivu · 2010-03-26 04:37:33 6
move up through directories faster (set in your /etc/profile or .bash_profile)

Usage: up N I did not like two things in the submitted commands and fixed it here: 1) If I do cd - afterwards, I want to go back to the directory I've been before 2) If I call up without argument, I expect to go up one level It is sad, that I need eval (at least in bash), but I think it's safe here. eval is required, because in bash brace expansion happens before variable substitution, see http://rosettacode.org/wiki/Repeat_a_string#Using_printf
This is sample output - yours may be different.
6

function up { cd $(eval printf '../'%.0s {1..$1}) && pwd; }

michelsberg · 2013-01-21 12:57:45 8
Bitcoin Brainwallet Base58 Encoder

A bitcoin "brainwallet" is a secret passphrase you carry in your brain. The Bitcoin Brainwallet Private Key Base58 Encoder is the third of three functions needed to calculate a bitcoin PRIVATE key from your "brainwallet" passphrase. This base58 encoder uses the obase parameter of the amazing bc utility to convert from ASCII-hex to base58. Tech note: bc inserts line continuation backslashes, but the "read s" command automatically strips them out. I hope that one day base58 will, like base64, be added to the amazing openssl utility. Show Sample Output
This is sample output - yours may be different.
```
> b58encode 0123456789abcdef
> C3CPq7c8PY
```
6

function b58encode () { local b58_lookup_table=({1..9} {A..H} {J..N} {P..Z} {a..k} {m..z}); bc<<<"obase=58;ibase=16;${1^^}"|(read -a s; for b58_index in "${s[@]}" ; do printf %s ${b58_lookup_table[ 10#"$b58_index" ]}; done); }

nixnax · 2014-02-18 02:29:30 14
Function to output an ASCII character given its decimal equivalent

I've corrected the function. My octal conversion formula was completely wrong. Thanks to pgas at http://mywiki.wooledge.org/BashFAQ/071 for setting me straight. The new function is from pgas and is very fast. Show Sample Output
This is sample output - yours may be different.
```
$ chr 65
A
```
5

chr () { printf \\$(($1/64*100+$1%64/8*10+$1%8)); }

dennisw · 2009-10-15 07:01:54 9
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Get size of terminal

See the cols and lines and make sure the console it correctly configured for the screen size.

Capture data in ASCII. 1500 bytes

Sniffing traffic on port 80 only the first 1500 bytes

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"

list all file-types (case-insensitive extensions) including subdirectories

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"

Shutdown a Windows machine from Linux

This will issue a shutdown command to the Windows machine. username must be an administrator on the Windows machine. Requires samba-common package installed. Other relevant commands are: net rpc shutdown -r : reboot the Windows machine net rpc abortshutdown : abort shutdown of the Windows machine Type: net rpc to show all relevant commands

Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)

Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.

Exclude inserting a table from a sql import

Starting with a large MySQL dump file (*.sql) remove any lines that have inserts for the specified table. Sometimes one or two tables are very large and uneeded, eg. log tables. To exclude multiple tables you can get fancy with sed, or just run the command again on subsequently generated files.

Install pip with Proxy

Installs pip packages defining a proxy

Umount only the NFS related to 'string'

Sometimes, you have a lot of NFS in the server and you can't or shouldn't use umount -a. Whis this command, you only umount the fs related to the 'string'

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Commands using printf (211)

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