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Check host port access using only Bash:
This is sample output - yours may be different.
0

s="$(cat 2>/dev/null < /dev/null > /dev/tcp/${target_ip}/${target_port} & WPID=$!; sleep 3 && kill $! >/dev/null 2>&1 & KPID=$!; wait $WPID && echo 1)" ; s="${s:-0}"; echo "${s}" | sed 's/0/2/;s/1/0/;s/2/1/'

wuziduzi · 2019-04-19 17:13:38 0
Network Discover in a one liner
This is sample output - yours may be different.
0

nmap -sn 192.168.1.0/24 -oG - | awk '$4=="Status:" && $5=="Up" {print $0}'|column -t

wuziduzi · 2019-04-19 17:12:00 0
Show your current network interface in use
This is sample output - yours may be different.
0

route | grep -m1 ^default | awk '{print $NF}'

wuziduzi · 2019-04-19 17:03:49 0
Create a file and manipulate the date
This is sample output - yours may be different.
0

touch -d '-1 year' /tmp/oldfile

wuziduzi · 2019-04-19 17:01:16 0
Switch all connected PulseAudio bluetooth devices to A2DP profile

Tries to switch all audio devices to the A2DP profile for optimal sound quality. Useful for bluetooth speakers and headphones that always power up in HSP/HFP mode. Note however that this command is only a shorthand for the GUI, so it cannot fix stubborn BT controllers that leave your device stuck in HSP mode until a manual re-coupling.
This is sample output - yours may be different.
0

for card in $(pacmd list-cards | grep 'name: ' | sed 's/.*<$.*$>.*/\1/'); do pacmd set-card-profile $card a2dp_sink; done

lordtoran · 2019-04-18 18:01:45 0
check web server port 80 response header
This is sample output - yours may be different.
0

curl -I <IPaddress>

maxo · 2019-04-18 06:38:59 0
change user password one liner

change user password one liner
This is sample output - yours may be different.
-2

echo -e "linuxpassword\nlinuxpassword" | passwd linuxuser

aysadk · 2019-04-17 18:12:30 2
check web server port 80 response header

check web server port 80 response header Show Sample Output
This is sample output - yours may be different.
```
HTTP/1.1 200 OK
Server: Apache 2.4.1
Date: Wed, 17 Apr 2019 17:56:50 GMT
Content-Type: text/html
Content-Length: 307
Last-Modified: Sat, 14 Jan 2017 22:01:22 GMT
Connection: close
ETag: "587a9fb2-133"
X-Frame-Options: SAMEORIGIN
Accept-Ranges: bytes
```
0

(echo -e 'GET / HTTP/1.0\r\n\r\n';) | ncat <IPaddress> 80

aysadk · 2019-04-17 18:09:28 0
command shell generate random strong password

shell generate random strong password Show Sample Output
This is sample output - yours may be different.
```
NXuc2VjRcOhW7zyQDBhH
```
1

len=20; tr -dc A-Za-z0-9_ < /dev/urandom | head -c ${len} | xargs

aysadk · 2019-04-16 20:20:46 1
Use was ec2 describe instances to retrieve IAM roles for specific ec2 tag to css list

This allows you to get all instance profiles (roles) for a given set of tags. Lists it in CSV Show Sample Output
This is sample output - yours may be different.
```
"arn:aws:iam::111114168247:instance-profile/Yourole-Instance-Profile,i-01ab14691695a0fa1"
```
0

aws ec2 describe-instances --region us-east-1 --filters "Name=tag:YourTag,Values=YourValue" | jq '.["Reservations"]|.[]|.Instances|.[]|.IamInstanceProfile.Arn + "," +.InstanceId'

symgryph · 2019-04-15 16:33:41 1
See n most used commands in your bash history

You can append these commands to the bottom of the history file to access them easier with the Up key: sort ~/.bash_history|uniq -c|sort -n|tail -n 10|tr -s " "|cut -d' ' -f3- >> ~/.bash_history
This is sample output - yours may be different.
1

sort ~/.bash_history|uniq -c|sort -n|tail -n 10

knoppix5 · 2019-04-15 14:20:00 0
Remove multiple entries of the same command in .bash_history with preserving the chronological order

Only the first appearance of a repeated command in the history will be kept. Otherwise, if you prefer to keep last occurrence of a repeated command then maybe you can achieve that by including reverse input/output i.e with 'tac' command in expression above. To see statistics of removed repeated commands: diff --suppress-common-lines -y ~/.bash_history.bak ~/.bash_history|uniq -c|sort -n|tr -s " "|sed '/^ 1/d'|grep '<'
This is sample output - yours may be different.
0

cp -a ~/.bash_history ~/.bash_history.bak && perl -ne 'print unless $seen{$_}++' ~/.bash_history.bak >~/.bash_history

knoppix5 · 2019-04-15 12:39:09 0
To create files with specific permission:
This is sample output - yours may be different.
2

install -b -m 777 /dev/null file.txt

wuziduzi · 2019-04-13 02:52:35 0

Determining if a String Contains a Substring in Bash

Show Sample Output

stringContains() { [ -z "${2##*$1*}" ] && [ -z "$1" -o -n "$2" ]; }

mikhail · 2019-04-12 20:51:27 0

SSH Copy ed25519 key into your host
This is sample output - yours may be different.
1

ssh-copy-id -i your-ed25519-key user@host

fromthestone · 2019-04-11 02:23:46 0
Patator: A Hydra brute force alternative
This is sample output - yours may be different.
0

patator ssh_login host=192.168.1.16 port=22 user=FILE0 0=user.lst password=FILE1 1=pass.lst -x ignore:mesg='Authentication failed.'

ioshield · 2019-04-10 17:42:13 0
Calculate the distance between two geographic coordinates points (latitude longitude)

The Haversine formula determines the great-circle distance between two points on a sphere given their longitudes and latitudes. Show Sample Output
This is sample output - yours may be different.
```
# input (format: latitude1 longitude1 latitude2 longitude2) :

h -22.9077611 -43.1259322 -22.9121089 -43.2301558

# output:
10.6889

# So, the distance between -22.9077611 (latitude),-43.1259322 (longitude) and -22.9121089,-43.2301558 (latitude,longitude) is 10,688.9 meters (10.6889 kilometers)
```
2

h(){ echo $@|awk '{d($1,$2,$3,$4);} function d(x,y,x2,y2,a,c,dx,dy){dx=r(x2-x);dy=r(y2-y);x=r(x);x2=r(x2);a=(sin(dx/2))^2+cos(x)*cos(x2)*(sin(dy/2))^2;c=2*atan2(sqrt(a),sqrt(1-a)); printf("%.4f",6372.8*c);} function r(g){return g*(3.1415926/180.);}';}

mikhail · 2019-04-04 01:34:36 1
worse alternative to <ctrl+r>

worse alternative to ctrl+r: grep the history removing duplicates without sorting (case insensitive search). Show Sample Output
This is sample output - yours may be different.
```
history # history sample for reference:
1 echo "duplicate"
2 awk --help
3 echo "duplicate"
4 echo "ctrl+r is better"

# input:
memo echo

# output:
echo "duplicate"
echo "ctrl+r is better"
```
1

function memo() { history | grep -i $@ | awk '! seen[$2]++'; }

mikhail · 2019-04-04 00:54:43 0
du command without showing other mounted file systems
This is sample output - yours may be different.
1

du -h --max-depth=1 --one-file-system /

Ryangillan · 2019-04-02 22:47:24 0
Remove all matches containing a string until its next space

Remove all arguments related to linux kernel from a list which uses space as item separator.
This is sample output - yours may be different.
-1

sed 's/linux-[^ ]* \{0,1\}//g' /path/to/file

bugmenot · 2019-04-01 19:35:47 1

Enable Synology Debug mode on shell

Added gdb & other usefull stuff Show Sample Output

sudo synogear install && sudo su

dbiesecke · 2019-03-30 03:45:12 1

Bitcoin Brainwallet Private Key Calculator
This is sample output - yours may be different.
0

$ bitgen hex 12312381273918273128937128912c3b1293cb712938cb12983cb192cb1289b3 info

Label10 · 2019-03-27 21:25:29 1
Set pcap & SUID Bit for priv. network programs (like nmap)
This is sample output - yours may be different.
2

export BIN=`which nmap` && sudo setcap cap_net_raw,cap_net_admin+eip $BIN && sudo chown root $BIN && sudo chmod u+s $BIN

dbiesecke · 2019-03-27 16:04:07 0
Application network trace based on application name

This command takes an application name as an argument and then it will listen to the tcp traffic and capture packets matching the process Id of the application. The output shows: local address / local port / Remote Address / Remote port / State / Owning Process ID Show Sample Output
This is sample output - yours may be different.
```
192.168.0.1                      50306     8.8.8.8                       443        Established Internet       21128
```
1

while(1 -eq 1 ) {Get-Process -Name *APPNAME* | Select-Object -ExpandProperty ID | ForEach-Object {Get-NetTCPConnection -OwningProcess $_} -ErrorAction SilentlyContinue }

guillaume1306 · 2019-03-26 09:44:57 1
Check every URL redirect (HTTP status codes 301/302) with curl
This is sample output - yours may be different.
1

curl -sLkIv --stderr - https://exemple.com | awk 'BEGIN{IGNORECASE = 1};/< location:/ {print $3}'

rolanda · 2019-03-25 14:47:20 0
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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.

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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

Random Number Between 1 And 256

It takes a byte from /dev/random whose source is the kernel entropy pool (better source than other solutions).

Virtualbox rsync copy (without defining any virtualbox configuration)

That is, after running `vagrant ssh-config` to determine ports and ip's: $ vagrant ssh-config Host default HostName 127.0.0.1 User vagrant Port 2200 UserKnownHostsFile /dev/null StrictHostKeyChecking no PasswordAuthentication no IdentityFile /Users/romanvg/tmp/.vagrant/machines/default/virtualbox/private_key IdentitiesOnly yes LogLevel FATAL

Show exit status of all portions of a piped command eg. ls |this_doesn't_exist |wc

shut of the screen.

How To Get the Apache Document Root

Grabs the Apache config file (yielded from httpd) and returns the path specified as DocumentRoot.

list processes with established tcp connections (without netstat)

Uses lsof to list open network connections (file descriptors), grepping for only those in an established state

Nicely display mem usage with ps

Nicely display mem usage with ps.

find previously entered commands (requires configuring .inputrc)

[Click the "show sample output" link to see how to use this keystroke.] Meta-p is one of my all time most used and most loved features of working at the command line. It's also one that surprisingly few people know about. To use it with bash (actually in any readline application), you'll need to add a couple lines to your .inputrc then have bash reread the .inputrc using the bind command: $ echo '"\en": history-search-forward' >> ~/.inputrc $ echo '"\ep": history-search-backward' >> ~/.inputrc $ bind -f ~/.inputrc I first learned about this feature in tcsh. When I switched over to bash about fifteen years ago, I had assumed I'd prefer ^R to search in reverse. Intuitively ^R seemed better since you could search for an argument instead of a command. I think that, like using a microkernel for the Hurd, it sounded so obviously right fifteen years ago, but that was only because the older way had benefits we hadn't known about. I think many of you who use the command line as much as I do know that we can just be thinking about what results we want and our fingers will start typing the commands needed. I assume it's some sort of parallel processing going on with the linguistic part of the brain. Unfortunately, that parallelism doesn't seem to work (at least for me) with searching the history. I realize I can save myself typing using the history shortly after my fingers have already started "speaking". But, when I hit ^R in Bash, everything I've already typed gets ignored and I have to stop and think again about what I was doing. It's a small bump in the road but it can be annoying, especially for long-time command line users. Usually M-p is exactly what I need to save myself time and trouble. If you use the command line a lot, please give Meta-p a try. You may be surprised how it frees your brain to process more smoothly in parallel. (Or maybe it won't. Post here and let me know either way. ☺)

Search and Replace across multiple files

- grep for the word in a files, use recursion (to find files in sub directories), and list only file matches -| xargs passes the results from the grep command to sed -sed -i uses a regular expression (regex) to evaluate the change: s (search) / search word / target word / g (global replace)

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