Linux Commands I Use

Commands I use repeatedly...

[linuxcommandsiuse]

Create python3 virtual env

python3 -m venv env

[linuxcommandsiuse]

Check free disk space

df -h

[linuxcommandsiuse]

Git favourites

Following are my git favourites:

Show a tree graph view won the terminal.

git log --graph --decorate

Git files that changed in a commit.

git show --stat --oneline <hash>

Show commit logs.

git log --oneline

Show difference between commits with changes.

git diff-tree -cc

Show git log with changes.

git log --cc

List of authors who committed to a repo

git shortlog -s -n --all --no-merges

[linuxcommandsiuse]

How to find the unix os information

cat /etc/os-release

[linuxcommandsiuse]

Check linux flavour

Usecase: Check the linux flavour

Command:

cat /proc/version

Also proc has a great set of other commands. Check what's available by doing

ls /proc/

[linuxcommandsiuse]

zip directory

Usecase Zip the current directory and create the zip file in the parent folder

Command

zip -r ./../filename.zip .

Example

zip -r ./../dummy.zip .

[linuxcommandsiuse]

Find if the process running the command

ps cax | grep nginx

[linuxcommandsiuse]

Find the process using a port

Following options show the process using port 80

netstat - Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships

sudo netstat -nlp | grep :80

lsof - list open files

sudo lsof -i :80 | grep LISTEN

[linuxcommandsiuse]

Start ssh-agent

Do the following in a command window to start the ssh agent service.

eval `ssh-agent -s`

[linuxcommandsiuse]

scp

Usecase: Copy file from local computer to remote using SSH

Command:

scp [options] username1@source_host:directory1/filename1 username2@destination_host:directory2/filename2

[linuxcommandsiuse]

apt-get update/upgrade

Usecase: Update linux packages

Commands:

sudo apt-get update # Fetches the list of available updates

sudo apt-get upgrade # Strictly upgrades the current packages

sudo apt-get dist-upgrade # Installs updates (new ones)

[linuxcommandsiuse]

meminfo

Usecase: When I need to check memory on the machine

Command: egrep --color 'Mem|Cache|Swap' /proc/meminfo

or

free -m

English: Gives a color column output of memory usage.

[linuxcommandsiuse]

setfacl

Usecase: When you need to define access rights to files and folders for more than one user group.

Command: setfacl -m <rules> <files>

Usage: setfacl -m g:mygroup:rwx /var/somefolder

English: Give user group mygroup read, write and execute access to the folder /var/somefolder

[linuxcommandsiuse]

netstat

Usecase: Find the program using a given port

Command: netstat -tulpn | grep :<port>

Usage: netstat -tulpn | grep :80

English: Who is using port 80

[linuxcommandsiuse]

su

Usecase: When I have multiple users and I want to switch from one to antoher:

Command: su <username>

Usage: su jerome. This will prompt you to enter the user password. Once you do that, the terminal session will be as that user

[linuxcommandsiuse]

nohup

Usecase: When you have a program running in the terminal and exits if you close the terminal.

Command: nohup

Usage: nohup ./someserverapp/bin/start.sh > /var/log/someserver-hohup.out&

English: Run the server start script and redirect the console out to the location I have given