3.1. linux

• 3.1.1. awk - manipulate text
  • 3.1.1.1. Separator
  • 3.1.1.2. awk can do math.
• 3.1.2. cat - print input to standard output
• 3.1.3. cd - change directories
• 3.1.4. chsh - change shell
• 3.1.5. cp - copy files or folders
  • 3.1.5.1. Copy Folders with cp -r
• 3.1.6. echo - Print Argument
• 3.1.7. grep - search for pattern in file or folders
• 3.1.8. head - read from top of file to standard output
• 3.1.9. help - read documentation
• 3.1.10. less - view files
• 3.1.11. ls - list information about files/folders
• 3.1.12. lsblk - list filesystem
• 3.1.13. man - documentation for various functions
• 3.1.14. mkdir - make new directories.
• 3.1.15. module - load software on slurm
• 3.1.16. mount - mount filesystem
• 3.1.17. mv - move files/folders from one place to another.
  • 3.1.17.1. Move/Rename Files and Folders
• 3.1.18. pwd - print working directory
• 3.1.19. rm - delete files
  • 3.1.19.1. Deleting Multiple Files
  • 3.1.19.2. Deleting Folders
• 3.1.20. rsync - sync files/folders
• 3.1.21. sbatch - Submit job to Slurm
• 3.1.22. scancel - Cancel Slurm Jobs
• 3.1.23. scp - copy files/folders over ssh
• 3.1.24. sed - tranform/replace text!
• 3.1.25. seq - sequence of numbers
• 3.1.26. setfacl - change file/folder permissions
• 3.1.27. sinfo - View information about Slurm nodes and partitions.
  • 3.1.27.1. Find idle partitions
• 3.1.28. sort - sorts lines
• 3.1.29. ssh - secure shell protocol
• 3.1.30. ssh-keygen - Make SSH key
• 3.1.31. tail - read from bottom of file
• 3.1.32. tar - compress/uncompress files
• 3.1.33. touch - Make File
• 3.1.34. trap - signalled execution

3.1.35. Reset GNOME Terminal Hotkeys

dconf reset -f /org/gnome/terminal/legacy/keybindings/

3.1.36. Manging Multiple Compiler Versions

• for personal machines

For example, if you need multiple versions of gcc/g++ on a single machine running Ubuntu 22.04

• First install with sudo apt-get

sudo apt-get install gcc-11 gcc-10 gcc-9 g++-11 g++-10 g++-9 -y

• Use the updalternativesate to create list of multiple gcc and g++ compiler alternatives

• Larger number = higher priority

  • here, gcc and g++ 11 is default

sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-9 0
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-9 0
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-10 1
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-10 1
sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-11 2
sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-11 2

• Check the available c and c++ compilers list on your system and select desired version by entering relevant selection number:

sudo update-alternatives --config gcc
sudo update-alternatives --config g++

• Sanity check

gcc --version
g++ --version