Handy Bash Shell Info
Make .sh executable
- chmod a+x ./pathto.sh
Add execute permissions to folder and all scripts inside:
- chmod 775 -R ./pathtofolder
Linux System Admin
System tools for fedora/red hat:
- DNS = system-config-bind
- HTTP = system-config-httpd
- NFS = system-config-nfs
- Root password = system-config-rootpassword
- Samba NFS = system-config-samba
- Services = system-config-services
- Authentication = authconfig-gtk
- Date & Time = system-config-date
- Firewall = system-config-firewall
- Language = system-config-language
- Printing = system-config-printer
- SELinux Management = policycoreutils-gui
- Users & Groups = system-config-users
- Configuration Editor = gconf-editor
- Disk Usage Analyzer = gnome-utils
- Disk Utility = gnome-disks
- Kickstart = system-config-kickstart
Enable service to run on boot:
- sudo systemctl enable <service>
- eg: sudo systemctl enable bluetooth.service
Linux Processes
- Show running processes: ps
- Show processes for all users: ps aux
- Display running processes: top
- List processes via config directory (services started at boot via script in this directory ): ls /etc/init.d or ls /etc/rc.d
- list all processes with specific columns ( use -o parameter ): ps -e -o %mem,pid,uid,comm
- Sort output of ps by cpu usage: ps -e --sort=%cpu
Get all processes:
- ps -e
Search for specific process:
- ps -e | grep <processname>
Kill process:
- kill <processID>
Enable SSH
Install the ssh client if not already installed:
- sudo apt install openssh-client
If you want to enable SSH on Ubuntu server, use the following command:
- sudo apt install openssh-server
If ssh in not being allowed remotely you will need to open port 22 on the firewall:
- sudo ufw allow 22
Linux Disk Space / Usage
Use the "df" command to see the disks mounted to the system
Can use df -BM to display output in blocksize megabytes or -h to output in human readable format
Use -T to disply the type of file system the mounted disk is
Use -x to exclude a type of file system eg
- df -x squashfs --total
Use -t to only include a type of filesystem eg
- df -t ext4
You can specify report of specific named file systems eg:
- df -h --total /dev /run
Use "du" command to show folder disk usage eg:
- du
- du -BM
- du -h
Sort output by largest to smallest size
- du -sm | sort -nr
Use du to find biggest files and sort the output:
- sudo du -a | sort -n -r | head -n 20
Reset Accounts
If you are unable to access a linux VM hold down shift on boot to get into GRUB menu. Select Advanced Options then boot from the last recovery version.
In the options select drop to root shell prompt
For the account that needs to be reset use the passwd command:
- passwd <username>
This will allow to change the password of root or any other user.