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shuffle lines via perl

Same, without modules... Probably smarter option: just use the shuf command or even sort -R. Show Sample Output
This is sample output - yours may be different.
```
6
9
8
1
7
2
3
5
4
```
2

seq 1 9 | perl -e 'print sort { (-1,1)[rand(2)] } <>'

MarxBro · 2019-07-03 20:02:00 1
shuffle lines via perl
This is sample output - yours may be different.
0

seq 1 9 | perl -MList::Util=shuffle -e 'print shuffle <>;'

emphazer · 2019-07-03 09:39:08 0
extract column from csv file
This is sample output - yours may be different.
0

cut -d"," -f9

xtrboy · 2019-07-02 19:59:59 0
create ext4 filesystem with big count of inodes

XX is your device partition number like /dev/sdc1 . to see how many inodes your partition have type: df --inodes (or df -i) Default formatting with ext4 would create small inode count for the new partition if you need big count of inodes is the fstype news the correct one. in debian you can see which fstype exists as template in: vim /etc/mke2fs.conf if you format default ext for a partition size with 1TB you would get 1 Million inodes (not enough for backupStorages) but if you format with fstype news you would get hunderd of millions of inodes for the partition. you have tune /etc/sysctl.conf also with following sysconfig parameters fs.file-max = XXX fs.nr_open = XXX where XXX is the count of max inodes for whole system
This is sample output - yours may be different.
1

mkfs.ext4 -T news /dev/sdcXX

aysadk · 2019-07-02 13:31:23 0
print DateTimeOriginal from EXIF data for all files in folder

see output from `identify -verbose` for other keywords to filter for (e.g. date:create, exif:DateTime, EXIF:ExifOffset). Show Sample Output
This is sample output - yours may be different.
```
2019:06:01 11:08:21
2019:06:01 11:08:39
2019:06:01 11:09:01
2019:06:01 11:09:08
2019:06:01 11:09:17
```
2

for i in *.jpg; do identify -format %[EXIF:DateTimeOriginal] $i; echo; done

m4r14n0ju · 2019-07-02 10:55:51 0
find out which directory uses most inodes - list total sum of directoryname existing on filesystem
This is sample output - yours may be different.
1

find /etc -xdev -printf '%h\n' | sort | uniq -c | sort -k 1 -n

aysadk · 2019-07-02 09:13:53 0
get total of inodes of root partition
This is sample output - yours may be different.
1

du --total --inodes / | egrep 'total$'

aysadk · 2019-07-02 09:08:35 0

blktrace - generate traces of the i/o traffic on block devices

blktrace is a block layer IO tracing mechanism which provide detailed information about request queue operations up to user space. blkparse will combine streams of events for various devices on various CPUs, and produce a formatted output the the event information. It take the output of above tool blktrace and convert those information into fency readable form. Show Sample Output

This is sample output - yours may be different.

  8,0    1      307    16.300038018   364  G WFS 214877536 + 8 [dmcrypt_write]
  8,0    1      308    16.300038546   364  P   N [dmcrypt_write]
  8,0    1      309    16.300039823   364  I WFS 214877536 + 8 [dmcrypt_write]
  8,0    1      310    16.300040693   364  U   N [dmcrypt_write] 1
  8,0    1      311    16.300041212   364  D  WS 214877536 + 8 [dmcrypt_write]
  8,0    6     6055    16.743540891     0  C   R 581944 + 8 [0]
  8,0    7      478    16.743294229  1394  A   R 581944 + 8 <- (8,5) 80184
  8,0    7      479    16.743295236  1394  Q   R 581944 + 8 [ls]
  8,0    7      480    16.743300616  1394  G   R 581944 + 8 [ls]
  8,0    7      481    16.743302315  1394  I   R 581944 + 8 [ls]
  8,0    7      482    16.743304891  1394  D   R 581944 + 8 [ls]
  8,0    6     6056    18.155362789  1532  C   W 200588584 + 8 [0]
  8,0    1      312    18.155288246   364  A   W 200588584 + 8 <- (8,5) 200086824
  8,0    1      313    18.155289363   364  Q   W 200588584 + 8 [dmcrypt_write]
  8,0    1      314    18.155296277   364  G   W 200588584 + 8 [dmcrypt_write]
  8,0    1      315    18.155297452   364  P   N [dmcrypt_write]
  8,0    1      316    18.155299709   364  I   W 200588584 + 8 [dmcrypt_write]
  8,0    1      317    18.155300975   364  U   N [dmcrypt_write] 1
  8,0    1      318    18.155302739   364  D   W 200588584 + 8 [dmcrypt_write]
  8,0    0        1 1266874889.707513405   364  A  WS 214877096 + 8 <- (8,5) 214375336
  8,0    0        2 1266874889.707514373   364  Q  WS 214877096 + 8 [dmcrypt_write]
  8,0    0        3 1266874889.707518565   364  G  WS 214877096 + 8 [dmcrypt_write]
  8,0    0        4 1266874889.707519046   364  P   N [dmcrypt_write]
  8,0    0        5 1266874889.707519640   364  A  WS 214877104 + 8 <- (8,5) 214375344
  8,0    0        6 1266874889.707519776   364  Q  WS 214877104 + 8 [dmcrypt_write]
  8,0    0        7 1266874889.707521386   364  M  WS 214877104 + 8 [dmcrypt_write]
  8,0    0        8 1266874889.707521635   364  A  WS 214877112 + 8 <- (8,5) 214375352
  8,0    0        9 1266874889.707522030   364  Q  WS 214877112 + 8 [dmcrypt_write]
  8,0    0       10 1266874889.707522365   364  M  WS 214877112 + 8 [dmcrypt_write]
  8,0    0       11 1266874889.707522530   364  A  WS 214877120 + 8 <- (8,5) 214375360
  8,0    0       12 1266874889.707522636   364  Q  WS 214877120 + 8 [dmcrypt_write]
  8,0    0       13 1266874889.707522845   364  M  WS 214877120 + 8 [dmcrypt_write]
  8,0    0       14 1266874889.707522975   364  A  WS 214877128 + 8 <- (8,5) 214375368
  8,0    0       15 1266874889.707523072   364  Q  WS 214877128 + 8 [dmcrypt_write]
  8,0    0       16 1266874889.707523245   364  M  WS 214877128 + 8 [dmcrypt_write]
  8,0    0       17 1266874889.707524366   364  I  WS 214877096 + 40 [dmcrypt_write]
  8,0    0       18 1266874889.707525418   364  U   N [dmcrypt_write] 1
  8,0    0       19 1266874889.707526516   364  D  WS 214877096 + 40 [dmcrypt_write]
CPU0 (8,0):
 Reads Queued:         303,     1212KiB	 Writes Queued:         752,     3464KiB
 Read Dispatches:      277,     1196KiB	 Write Dispatches:       68,      272KiB
 Reads Requeued:         0		 Writes Requeued:        26
 Reads Completed:        0,        0KiB	 Writes Completed:        0,        0KiB
 Read Merges:           22,       88KiB	 Write Merges:          264,     1056KiB
 Read depth:           576        	 Write depth:            36
 IO unplugs:            42        	 Timer unplugs:          11

sudo blktrace -d /dev/sda -o - | blkparse -i -

emphazer · 2019-07-02 06:13:58 0

draw line separator (using knoppix5 idea)
This is sample output - yours may be different.
2

printf '*%.s' {1..40}; echo

metropolis · 2019-07-01 07:41:18 0
draw line separator (using knoppix5 idea)

This is a slightly modified version of the knoppix5 user oneliner (https://www.commandlinefu.com/commands/view/24571/draw-line-separator). Show Sample Output
This is sample output - yours may be different.
```
$ seq -s '*' 40 | tr -dc '[*\n]'
***************************************
```
1

seq -s '*' 40 | tr -dc '[*\n]'

acavagni · 2019-07-01 07:24:47 0
colorize sequences of digits

Credits go to Flatcap https://www.commandlinefu.com/commands/by/flatcap
This is sample output - yours may be different.
1

echo abcd89efghij340.20kl|grep --color -e "[0-9]\+" -e "$"

knoppix5 · 2019-06-30 15:06:28 2
draw line separator

Even shorter: seq -s '*' 120|tr -d '[0-9]'
This is sample output - yours may be different.
2

seq -s '*' 40|tr -c '*' '*' && echo

knoppix5 · 2019-06-30 13:40:53 3
simplest calculator
This is sample output - yours may be different.
1

echo $[321*4]

knoppix5 · 2019-06-30 12:43:55 0
Comparison between the execution output of the last and penultimate command

Useful for checking if there are differences between last and penultimate command.
This is sample output - yours may be different.
2

diff <(!!) <(!-2)

rolanda · 2019-06-30 10:41:02 1
Generate a random password 30 characters long
This is sample output - yours may be different.
1

tr -c -d "a-zA-Z0-9" </dev/urandom | dd bs=30 count=1 2>/dev/null;echo

tlezotte · 2019-06-29 22:46:41 0
Sort processes by CPU Usage
This is sample output - yours may be different.
2

ps auxk -%cpu | head -n10

rolanda · 2019-06-29 19:17:14 0
Show your current network interface in use
This is sample output - yours may be different.
1

ip r show default | awk '{print $5}'

rolanda · 2019-06-29 16:13:23 0
Generate a random password 30 characters long
This is sample output - yours may be different.
1

openssl rand -rand /dev/urandom -base64 30

rolanda · 2019-06-29 14:55:15 1
unset all http proxy related environment variables in one go in the current shell

Show Sample Output
This is sample output - yours may be different.
```
$ printenv | grep -i proxy
NO_PROXY=.somedomain.sometld,10.0.0.0/8
http_proxy=http://localhost:3128/
HTTPS_PROXY=http://localhost:3128/
https_proxy=http://localhost:3128/
HTTP_PROXY=http://localhost:3128/
$ eval "unset $(printenv | grep -ioP '(?:https?|no)_proxy' | tr '\n' ' ')"
$ printenv | grep -i proxy
$
```
0

eval "unset $(printenv | grep -ioP '(?:https?|no)_proxy' | tr '\n' ' ')"

acavagni · 2019-06-28 10:40:41 0
This will take the last two commands from bash_history and open your editor with the commands on separated lines
This is sample output - yours may be different.
2

fc -1 -2

wuziduzi · 2019-06-22 23:56:40 2
Alert visually until any key is pressed

I learned a few things reading this command. But I did run into a few issues: 1. On systems that don't use GNU echo (e.g. macOS 10.14.5 Mojave), the e option may not be supported. In this case ANSI escape codes will echoed as text and the terminal will not flash, like this: \e[?5h\e[38;5;1m A L E R T Thu Jun 20 16:31:29 PDT 2019 2. Since the read command strips\ignores leading backslashes, if a user types the backslash character once in the loop, it will not break. Typing backslash twice in a loop will break as expected. 3. The foreground color is set to red (\e[38;5;1m) on every loop. This could be set once before we call while, and then reset once when the loop breaks. 4. Instead of resetting the foreground color when it breaks, the video mode is set back to normal (\e[?5l). This has the effect of leaving the terminal text red until it is manually reset. The alternative I'm proposing here addresses these issues. I tested it on macOS and Arch Linux. Show Sample Output
This is sample output - yours may be different.
```
 A L E R T Thu Jun 20 16:31:29 PDT 2019
 A L E R T Thu Jun 20 16:31:30 PDT 2019
```
1

printf "\e[38;5;1m"; while true; do printf "\e[?5h A L E R T %s\n" "$(date)"; sleep 0.1; printf "\e[?5l"; read -r -s -n1 -t1 && printf "\e[39m" && break; done

z80a · 2019-06-21 00:05:16 0
Alert visually until any key is pressed
This is sample output - yours may be different.
3

while true; do echo -e "\e[?5h\e[38;5;1m A L E R T $(date)"; sleep 0.1; printf \\e[?5l; read -s -n1 -t1 && printf \\e[?5l && break; done

knoppix5 · 2019-06-18 15:27:36 1
Generrate Cryptographically Secure RANDOM PASSWORD

Change :alnum: to :graph: for all printable characters Show Sample Output
This is sample output - yours may be different.
```
FH170AB1DXb4dHlX
```
-2

cat /dev/urandom |tr -c -d '[:alnum:]'|head -c 16;echo

AndrewM · 2019-06-17 17:51:04 0
automatically generate the ip/hostname entry for the /etc/hosts in the current system

I use it after a clean CentOS 7 minimal server installation to automatically populate the /etc/hosts file. Not sure why the installation does not add this entry by itself. Tested on CentOS 7 with the simplest use case: 1 static ip address and the hostname provided during installation. Show Sample Output
This is sample output - yours may be different.
```
[[email protected] ~]# echo "$(ip addr show dev $(ip r | grep -oP 'default.*dev \K\S*') | grep -oP '(?<=inet )[^/]*(?=/)') $(hostname -f) $(hostname -s)"
10.0.2.10 dns-server.mydomain.lab dns-server

[[email protected] ~]# echo "$(ip addr show dev $(ip r | grep -oP 'default.*dev \K\S*') | grep -oP '(?<=inet )[^/]*(?=/)') $(hostname -f) $(hostname -s)" >> /etc/hosts

[root[email protected] ~]# cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
10.0.2.10 dns-server.mydomain.lab dns-server
```
0

echo "$(ip addr show dev $(ip r | grep -oP 'default.*dev \K\S*') | grep -oP '(?<=inet )[^/]*(?=/)') $(hostname -f) $(hostname -s)"

acavagni · 2019-06-15 16:40:38 2
Autocomplete directories (CWDs) of other ZSH processes (MacOS version)

MacOS Solution due to lack of pidof command and procfs on MacOS Kernel. Show Sample Output
This is sample output - yours may be different.
```
[ [email protected] ~/scripts ]$ xcd <TAB>
/Users/name/scripts              /Users/name/scripts/Boltdir
/usr/local/bin                   /var/log/
```
0

function _xterm_cwds() { for pid in $(pgrep -x zsh); do reply+=$(lsof -p $pid | grep cwd | awk '{print $9}') done }; function xcd() { cd $1 }; compctl -K _xterm_cwds xcd

cdiehl · 2019-06-15 02:26:11 0
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Fix the vi zsh bindings on ubuntu

Use sed to comment out any up/down bindings in zsh

Start COMMAND, and kill it if still running after 5 seconds

Fast, built-in pipe-based data sink

This is shorter and actually much faster than >/dev/null (see sample output for timings) Plus, it looks like a disappointed face emoticon.

Convert CSV to JSON

Replace 'csv_file.csv' with your filename.

Report the established connections for a particular port

get the oldest file in a directory

reverse the sorting of ls to get the newest file: $ls -1tr --group-directories-first /path/to/dir/ | tail -n 1 Problems: If there are no files in the directory you will get a directory or nothing.

Binary difference of two files

Upload/download newer version of any file with less size and high speed. To remake the new file use $bspatch

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"

Introduction to user commands

Tested on debian and ubuntu. Translations could be useless, so "LANG=C man intro" is a better alternative.

Find the package that installed a command

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