Some useful skills for better Linux user experience.

1. sources.list

if you are living in China, it is a good idea to change the sources of repository for you linux system.

the sources are in /etc/apt/sources.list file, you can back up the default sources.list with sudo cp /etc/apt/sources.list ~/Document/sources_backup.list

# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted universe multiverse

# 预发布软件源，不建议启用
# deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-proposed main restricted universe multiverse

after adding the new sources, run sudo apt update. and sudo apt full-upgrade as optional action.

2. samba

samba is useful to transfer files between linux and windows machines.

2.1 set samba server

first install samba on your machine

sudo apt update
sudo apt install samba

then you need to set up samba

make a directory for samba to share withmkdir /home/<username>/sambashare/

back up your /etc/samba/smb.conf and edit it

sudo vim /etc/samba/smb.conf

adding the following lines

[sambashare]
    comment = Samba on Ubuntu
    path = /home/username/sambashare
    read only = no
    browsable = yes

the path is the absolute path (directory) you made for samba to share with

now enable and run the service with systemctl

sudo systemctl enable smbd
sudo systemctl restart smbd

# check smbd service status
sudo systemctl status smbd

allow samba traffic on firewall

sudo ufw allow samba

setting up user account for samba

sudo smbpasswd -a username

Note! the user should exist on the machine you set up the samba server.

2.2 samba client

connect on linux gui

on file explorer, use connect to server

smb://ip_address/sambashare

on windows, open file explorer, and on address bar

\\ip_address\sambashare

Note! the path for client is ip_address/sambashare, which was in square bracket in smb.conf file, keep it same as [sambashare] you configured on the server

2.2.1 smbclient

you can use samba on terminal with smbclient

simply sudo apt install smbclient

to connect samba server on terminal

smbclient //ip_address/sambashare -U username

enter password for user, and you are good to go.
you can use ls, cd, pwd, and so on in smbclient.
to fetch a remote file to local machine

get file_name

to upload a file from local machine to server

put file_name

Note! you local working directory is the directory where you run smbclient program, and remote current directory can be shown as pwd.

to exit smbclient on terminal, type exit

3. execute or source a file

execute a file will run the file in a new shell process, to execute a file

./file_name

# or

file_name

source a file will run the file in current shell process, to source a file

source file_name

# or 

. file_name

Note ! dot is an alias to source in UNIX

3. Sed (stream editor)

3.1 simple subsitute

sed "s/old_text/newtext/" foo.txt

3.2 sed with multiple commands

sed -e "s/old/new"; "s/today/tomorrow/" foo.txt

add an -e option, Note ！ no space between end of command and ;

3.3 save scripts in a sed file

cat script1.sed

s/black/white/
s/good/super/
s/hi/hello/

you can call the sed file with -f optionsed -f script1.sed foo.txt

Chao216 / useful-linux