Some reviews:

Kali Linux

/bin/
/sbin/ system programs
/etc/ files
/tmp/ temporay file delete on boot
/usr/bin/ user binary
/usr/share application support files

Linux Commands:

man -k passwd:  key word search
└─$ man -k '^passwd$'  
passwd (1)           - change user password
passwd (1ssl)        - compute password hashes
passwd (5)           - the password file
man 5 passwd

apropos == man -k

ls -a1
-1 means one file each line
cd, mkdir, pwd
with space:
cd module\ one/
mkdir -p /hello/world/{recon, exploit, report}

Finding files in kali linux

find, locate, which

locate seach a built in database instead of harddisk, can be update manually. sudo updatedb

find can search size, type….

sudo find / -name sbd*

manage linux services

sudo systemctl start ssh
sudo ss -antlp | grep sshd
ss  is  used to dump socket statistics.

-a all
-n numerical
-t tcp
-l listening
-p display process

list all available services:

systemctl list-unit-files

Search/install/remove tools

sudo apt update
sudo apt upgrade <package-name>

apt-cache search pure-ftpd search if package exist, search in package description
apt show <pacage-name> show the description
apt install <package-name>
apt remove –purge completely remove the package including user configurations

sudo dpkg -i <path to the package file.deb> will not install any dependency

Commandline

Some environment variables:

$PATH, $USER, $PWD, $HOME

define EV:

export b=10.11.1.220
ping -c 2 $b

without export, only affect current bash, not inherit by spawning bash

env

Bash history

history
!32   # replay line 32
!!    # repeat the last command

saved in ~/.bash_history
$HISTSIZE, $HISTFILESIZE
CTRL+R reverse-i-search looking for most recent matched command

Pipline and redirection

0 STDIN, 1 STDOUT, 2 STDERR

Redirect to a new file:
echo "test" > test.txt
Redirect to an existing file:
echo "test" >> test.txt
Redirect from a file:
wc -m < test.text connect the file to the STDIN of wc
Redirect STDERR
ls ./test 2>error.txt

Piping

cat error.txt | wc -m output of cat to input of wc

Text searching

ls -la /usr/bin | grep zip
-r recursive search
-i ignore case
sed:
echo "I need to try hard" | sed 's/hard/harder/'
cut:
echo "hello, world, ???" | cut -f 2 -d ","
-f field
-d delimiter
can only acce[t single char delimiter
echo "hello::there::friend" | awk -F "::" '{print $1, $3}'
-F field separator

cat access.log | cut -d " " -f 1 | sort -u
cat access.log | cut -d " " -f 1 | sort | uniq -c | sort -urn

-n compare according to string numerical value
-r reverse the result of comparisons

Nano

Ctrl + K cut the line
Ctrl + U paste the line
Ctrl + W search in the file

Vim

dd delete current line
yy copy the current line
p to paste the clipboard content
x delete the char under the current cursor

File comparison

comm file1 file2 unique line in file1. file2, and in both file
comm -12 file1 file2 supress col1,2, only display lines in both files
diff -c/-u
vimdiff Ctrl + W + arrow switch window
[/] + c jump to prev/next change
d+o get the change in other window and put to the current one
d+p put the change in current window and put to the other one

Manage processes

background process

Ctrl + Z to suspend it, then resume it using bg

jobs shows the jobs in the current terminal
fg %[jobnum] return the job to the foreground

ps -ef
-e, –everyone show processes of all users
-f, –full show process uids, ppids

File and Command Monitoring

tail and watch
watch run command every 2 second

watch -n 5 w

w - Show who is logged on and what they are doing.
-n every 5 seconds

Download Files:

wget -O [dest] [url]
curl -o [dest] [url]
axwl -a -n 50 -o [dest] [url]
-n number of connections use
-a Alternate progress indicator

Bash environment

export HISTCONTROL=ignoredups

System bash /etc/bash.bashrc