Save your disk, write files directly into RAM with /dev/shm

Thu, 26 Jun 2025 00:00:00 +0000

Given my interest in extending the life of my SD cards and hard drives as much as possible, I’m surprised I haven’t come across /dev/shm before. In a word it’s a world-accessible RAM scratchpad, which seems baked right into POSIX, so that virtually every ~~Unix~~ EDIT: Linux system already has it mounted as a tmpfs by default:

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❯ mount | grep '/dev/shm'
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,inode64)

Today’s lucky 10,000, indeed. It gets mentioned often in Hacker News comments, but surprisingly I couldn’t find any actual articles talking about it. The existence of /dev/shm is a boon for me mostly because it means I never have to worry about whether /tmp is really RAM-based again.

Ramdisks on Andrew Quinn's TILs

Save your disk, write files directly into RAM with /dev/shm