update_alternatives.md

Creating symlink alternatives using update-alternatives on Linux

• Install a symlink alternative using --install flag.

sudo update-alternative --install {path to symlink: string} {name of alternative: string} {path to where to point that symlink alternative: string} {priority: number}

* `Path To Symlink` - usually always located in `/usr/bin/` (ex: `/usr/bin/python3` for creating alternatives to multiple python versions)
* `Name Of Alternative` - should always be the name of the symlink (ex: `python3` for `/usr/bin/python3`).
* `Path To Where To Point That Symlink Alternative` - location of the exucable to be set as a symlink alternative
* `Priority` - in auto mode, the alternative with the higher priority will be chosen
* Example full command: `sudo update-alternative --install /usr/bin/python python /usr/bin/python3`

• Edit the priority of an existing symlink alternative.

  • Use the same sudo update-alternative --install {existing path to symlink: string} {existing alternative: string} {existing path to binary: string} {priority: number} but change the priority and the priority of the exisitng alternative will be changed. (will not be duplicated)

• Config an alternative using --config flag.

sudo update-alternative --config {name of alternative: string}

* You will be prompted choose a number corresponding to the paths listed in an alternative.
* Selecting anything higher than 0 means you will switch to manual mode.
* Be default, alternatives are set in auto mode where paths are chosen according to highest priority.

• List all paths in an alternative using --list flag.

sudo update-alternatives --list {name of alternative: string}

• Remove all paths in an alternative using --remove-all flag.

sudo update-alternatives --remove-all {name of alternative: string}

• Remove one path in an alternative using --remove flag.

sudo update-alternatives --remove {name of alternative: string} {path to binary: string}