Finding System Information

• cat /etc/redhat-release → Red Hat version
• uname -a → Linux hostname, kernel, architecture
• dmidecode → hardware, BIOS, system info
• arch → x86_64 or i386/32-bit

Common Keyboard Shortcuts

• Ctrl + U → erase command line
• Ctrl + C → stop/kill current command
• Ctrl + Z → suspend command
• Ctrl + D → exit interactive session

Record Terminal Session

• script mylog.log → record shell session

  • Use exit to stop recording

Root Password Recovery

1. Reboot → enter GRUB menu
2. Press e → edit boot params
3. Add rd.break at end of kernel line
4. Ctrl + X to boot
5. Mount root with chroot /sysroot
6. passwd root → change password
7. touch /.autorelabel → SELinux relabeling on reboot

View Environment Variables

• printenv, echo $PATH, echo $SHELL

Set Environment Variables

• Temporary: export TEST=1, echo $TEST

• Permanent:

  vi ~/.bashrc
  TEST=123
  export TEST

Global → vi /etc/profile or /etc/bashrc