Some useful aliases for installing and working with NixOS

.profile

#!/usr/bin/env $SHELL
alias lsblk="lsblk -o MODEL,VENDOR,NAME,LABEL,SIZE,MOUNTPOINT,FSTYPE"
alias gramps="nix-env -p /nix/var/nix/profiles/system --list-generations"
alias nixos-rebuild="nixos-rebuild -j 6 --cores 8"
      #
      # -j is how many "jobs" or simultaneous computational processes run in tandem
      # --cores is how many CPU cores you want to use
      # How do you get these values? `cat /proc/cpuinfo` and look at the number of
      # returned "CPUs". They're zero indexed, so if you get the last one as object
      # number seven (7), you have 8 cores.
      # From there, I just subtract a few to give the operating system "breathing
      # room" from a cpu throughput perspective and boom, max number of jobs.
      #

# NOTES ON INSTALLING NIXOS
#
# For AMD graphics cards, DO NOT use the "ati_unfree" driver mentioned in the docs;
# it's over a year old and cost me 14+ hours of my life I'll never get back. Instead,
# use ONLY the "amdgpu-pro" driver. (For now, who knows when that'll next change?)
#
# START in UEFI mode. Always. Disable Windows System Protection nonsense in your BIOS
# first, just in case.
#
# AM I IN UEFI MODE?
#   ls /sys/firmware/
#   # if "efi" is a directory that shows up, you're in efi mode
#
# HOW TO PREP A GIVEN DEVICE FOR INSTALLATION
#   Verify you've got the right one with the lsblk alias above.
#   Then, use `cgdisk` -- NOTE THE LETTER 'G' HERE, IT'S VITAL -- to partition
#   it as follows:
#
#   (assuming you want to install on /dev/sda)
#     /dev/sda1    EFIBOOT      512M            (partition code: EF00)
#     /dev/sda2    linuxswap    {SOME_VALUE}    (partition code: 8200)
#     /dev/sda3    {SOME_LABEL} {SOME_VALUE}    (partition code: 8300)
#
#   Values and how to get them:
#     For my swap, I like to match the swap partition to the same amount of system
#     memory I have, *unless I have an obscene amount of system memory*. In the case
#     of one machine I tried this on (a physical desktop I'm using as my daily driver)
#     it had a whopping 32GB of memory. Now, if I've filled THAT MUCH, and I haven't
#     something's already wrong. But rolling with NO swap? Ehh...that just don't feel
#     right, kinda like driving drunk without a seatbelt. So in this case I split the
#     difference down the middle - 16GB. Easy peasy.
#
#     As for the EFIBOOT partition, I feel half a gig is about right. Gives you room
#     to grow, copy kernels and raise all kinds of hell without wasting too much space
#     on your precious SSD.
#
#     Which brings us to /dev/sda3. This can be labeled anything you want (my early
#     attempts were things like "fuzzywuzzy" and "krypton"), but DON'T name it "nixos".
#     Why? Because that's the name/label of your installer "LiveCD!". Meaning anything
#     mounting **by label** might get the two confused. Not cool.
#
#     As for size, I just take whatever `cgdisk` gives me as the first and last contiguous
#     sector/node values such that I have these literally in **SEQUENTIAL ORDER ON THE DISK
#     BY SECTOR** _and_ **the last partition goes to the last node, filling the disk.**
#     No wasted space.
#
# FORMATTING THE FILESYSTEMS
#
#   After writing the partition table to the disk, and verifying it again with my `lsblk`
#   shortcut above, you can now format the partitions.
#
#     mkfs.fat -F 32 -n EFIBOOT /dev/sda1
#     mkswap -L linuxswap /dev/sda2
#     mkfs.ext4 -L YOUR-SYSTEM-NAME /dev/sda3
#
#   Once this is done you can mount the filesystem according to its proper pre-install layout.
#
# MOUNTING. THE RIGHT WAY.
#
#     mkdir  /mnt # might already exist, no problem; just make sure it's empty
#     mount  /dev/disk/by-label/YOUR-SYSTEM-NAME /mnt -o noatime,discard # omit discard if NOT solid state
#     mkdir  /mnt/boot
#     mount  /dev/disk/by-label/EFIBOOT /mnt/boot # this is your EFI boot partition
#     swapon /dev/sda2
#
#   You now have a properly laid-out system mounted. Verify with `df -H`. You want:
#     /dev/sda1 => UEFI boot partition, blank, FAT32 formatted (nothing else works) mounted at /mnt/boot
#     /dev/sda2 => Linux swap partition; ensure that it's actually running just in case the build gets
#                  hairy by running "free -m". Is there a line reading "swap" at the bottom? Yes? Good.
#     /dev/sda3 => Linux EXT4 filesystem mounted at /mnt. It should be blank at this point (maybe a
#                  lost+found dir but nothing else)
#
#   Finally. You're ready to run the hardware config generation script.
#
# GENERATE THE BASE CONFIGURATION
#
#   This handy-dandy command will jot down information about your disks **AS THEY'RE PRESENTLY MOUNTED**
#   which is why we went to the trouble of doing it "by label" and with the right mount options earlier.
#   It also specifies what kernel modules you might need during systemd's UEFI boot process. And other
#   basic stuff. Then it generates the all-important /etc/nixos/configuration.nix file.
#
#   Run this:
#
#     nixos-generate-config --root /mnt 
#
#   You should now have two files in /mnt/etc/nixos/
#     configuration.nix
#     hardware-configuration.nix
#
#   DON'T TOUCH THE HARDWARE CONFIGURATION FILE, DAMN IT! Trust me on this. Don't. Do. It.
#   Instead, hax up that configuration.nix file to your liking. Now you see about installing the OS.
#
# INSTALLATION. FINALLY.
#
#   Run the following to _attempt_ to install. Warning: Every configuration mistake you make,
#   God kills a kitten.
#
#     nixos-install -j 6 --cores 8 --root /mnt --show-trace
#
#   Explanations of -j and --cores are the same as above. --root /mnt just tells it where you want your
#   fs root to be in the end. --show-trace is important here, especially when you haven't done this before,
#   because the options for settings in configuration.nix aren't well documented (if at all), wildly
#   inconsistent, and frequently conflict one another. You'll have to weed through these one-by-one.
#   Press on and push through the pain.
#
#   Finally, you _should_ get a working build. Run echo $? and if that's zero, run the simple command, reboot.
#