Tag: linux

Mount cifs/samba share inside container

#Dockerfile
FROM ubuntu
RUN apt update -y
RUN apt install  cifs-utils -y

docker build -t cifs .
docker run -it --cap-add SYS_ADMIN --cap-add DAC_READ_SEARCH   -cap-add NET_BIND_SERVICE cifs bash
#centos with privileged (working)

docker run --privileged -it --cap-add SYS_ADMIN --cap-add DAC_READ_SEARCH --cap-add NET_BIND_SERVICE centos bash
mount -t cifs -o username=a,password=a //192.168.0.228/public /mnt
mount -t cifs -o username=a,password=a //192.168.0.228/public /mnt
mount -t cifs -o username=a,password=a,ro,domain=WORKGROUP //192.168.0.228/public /a -v

Tmux , Screen, Nohup, – Run command in background

Why?
– Run process in background
– Run database backup in background

Tmux:

#List
tmux ls

#Start session
tmux new -s mysession

#Reconnect  
tmux a -t session_name

#Disconnect
ctrl + b + D


#Reconnect to 0 session
tmux a -t 0

More : https://tmuxcheatsheet.com

Screen :

#List
screen -ls

#Named session
screen -A -m -d -S session_name command

#Reconnect to named session
screen -r session_name 

#Disconnect
CTRL + a + d

https://gist.github.com/jctosta/af918e1618682638aa82

Nohup:

Nohup command &

It’s create nohup.out file in same directory with all command logs

https://www.thegeekdiary.com/nohup-command-examples-runs-a-command-that-keeps-running-after-you-log-out/

Jobs:

jobs
fg
bg

https://tldp.org/LDP/abs/html/x9644.html

Strings command in linux

strings /lib64/libc.so.6 |grep GLIBC

strings /bin/ls


Usage: strings [option(s)] [file(s)]
 Display printable strings in [file(s)] (stdin by default)
 The options are:
  -a - --all                Scan the entire file, not just the data section [default]
  -d --data                 Only scan the data sections in the file
  -f --print-file-name      Print the name of the file before each string
  -n --bytes=[number]       Locate & print any NUL-terminated sequence of at
  -<number>                   least [number] characters (default 4).
  -t --radix={o,d,x}        Print the location of the string in base 8, 10 or 16
  -w --include-all-whitespace Include all whitespace as valid string characters
  -o                        An alias for --radix=o
  -T --target=<BFDNAME>     Specify the binary file format
  -e --encoding={s,S,b,l,B,L} Select character size and endianness:
                            s = 7-bit, S = 8-bit, {b,l} = 16-bit, {B,L} = 32-bit
  -s --output-separator=<string> String used to separate strings in output.
  @<file>                   Read options from <file>
  -h --help                 Display this information
  -v -V --version           Print the program's version number
strings: supported targets: elf64-x86-64 elf32-i386 elf32-iamcu elf32-x86-64 a.out-i386-linux pei-i386 pei-x86-64 elf64-l1om elf64-k1om elf64-little elf64-big elf32-little elf32-big pe-x86-64 pe-bigobj-x86-64 pe-i386 plugin srec symbolsrec verilog tekhex binary ihex

connect to wifi using terminal in ubuntu

1.Create file and add wifi name and creds (vi /etc/wpa_supplicant.conf)

network={
    ssid="ssid_name"
    psk="password"
}

2.Connect

sudo wpa_supplicant -B -i wlan0 -c /etc/wpa_supplicant.conf -D wext
sudo dhclient wlan0

More : https://askubuntu.com/questions/138472/how-do-i-connect-to-a-wpa-wifi-network-using-the-command-line

https://askubuntu.com/questions/294257/connect-to-wifi-network-through-ubuntu-terminal

sftp setup to restrict user to some /path

WHY?
– Secure access
– Secure path

adduser kool -s /sbin/nologin

#edit /etc/ssh/sshd_config and ADD

Subsystem sftp internal-sftp
   Match User kool
   ChrootDirectory /opt/dir1/dir2
   ForceCommand internal-sftp
   X11Forwarding no
   AllowTcpForwarding no


chown root:root -R /opt/dir1/dir2
chmod 755 -R /opt/dir1/dir2

chown kool:kool /opt/dir1/dir2/kool
chmod 700 /opt/dir1/dir2/kool

iptables port allow/block

//Block port 8080

iptables  -A INPUT -p tcp --dport 8080 -j DROP

//Allow port 8080

iptables -A INPUT -p tcp -m tcp --dport 8080 -j ACCEPT

//Delete rule from same command(-D)

iptables  -D INPUT -p tcp --dport 8080 -j DROP

//Delete iptable rule for 8080 as per line number

iptables -L --line-numbers
iptables -D INPUT 1

//List rules

iptables -S
iptables -S TCP
iptables -L INPUT
iptables -L INPUT -v

#save
service iptables save