Throughout this book, the environment variable LFS will be used several times. It is paramount that this variable is always defined. It should be set to the mount point chosen for the LFS partition. Check that the LFS variable is set up properly with:
Make sure the output shows the path to the LFS partition's mount point, which is /mnt/lfs if the provided example was followed. If the output is incorrect, the variable can be set with:
Having this variable set is beneficial in that commands such as mkdir $LFS/tools can be typed literally. The shell will automatically replace “$LFS” with “/mnt/lfs” (or whatever the variable was set to) when it processes the command line.
Do not forget to check that $LFS is set whenever you leave and reenter the current working environment (as when doing a su to root or another user).