Linux Basic Commands

Notes on rights

400 read by owner 040 read by group 004 read by anybody 200 write by owner 020 write by group 002 write by anybody 100 execute by owner 010 execute by group 001 execute by anybody

Search for text in files recursively

The following grep will return each filename containing the given text :

grep -Ril "text"

• -R Read all files under each directory, recursively.

• -i case-insensitive search

• -l Print the file name for each match. This is the default when there is more than one file to search.

Search for Email Adresses Recursively

The following grep will match all email adresses @gmail.com :

grep -RIHEo "\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,6}\b" . | grep gmail.com

• -R Read all files under each directory, recursively.

• -I Process a binary file as if it did not contain matching data.

• -H Print the file name for each match. This is the default when there is more than one file to search.

• -E Interpret PATTERN as an extended regular expression.

• -o Print only the matched (non-empty) parts of a matching line, with each such part on a separate output line.

To generate list file from addresses found :

grep -RhIEo "\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,6}\b" . | grep gmail.com | sort -u > mails.txt

• -h disables filename printing

• sort -u removes duplicates

List Open Files For Process

lsof -p PID

• PID = Process ID

Display files and folders sorted by size

Ascending

du -hs ~/web/* | sort -h

Descending

du -hs ~/web/* | sort -hr

Network setup

Disable NetworkManager

systemctl disable NeworkManager

Set static IP with NetworkManagercomputer :: Documents/projects/PentestFTW »

Set IP

nmcli con mod My\ Connection ipv4.addresses 10.1.1.250/24

Set Gateway

nmcli con mod My\ Connection ipv4.gateway 10.1.1.1

Set DNS

nmcli con mod My\ Connection ipv4.dns 8.8.8.8     

Set connection up

nmcli con up My\ Connection

Connect to wifi with wpa_supplicant

Scan available ESSID

sudo iwlist wlo1 scan | grep ESSID | sort -u

Generate config for ESSID

wpa_passphrase mySSID myPass | sudo tee -a /etc/wpa_supplicant/wpa_supplicant.conf

Connect to wifi

sudo wpa_supplicant -c /etc/wpa_supplicant/wpa_supplicant.conf -i wlo1 -B

Obtain IP address via DHCP

sudo dhclient -v wlo1

Set static IP

Assign IP address to interface

sudo ip addr add 192.168.112.45/24 dev myNetworkInterface

Add default route

 sudo ip route add default via myGateway dev myNetworkInterface

Extract IP adresses from file

grep -E -o "([0-9]{1,3}[\.]){3}[0-9]{1,3}"