Some errors, just from the first few sections alone. From section 1: * "man hier" is out of date, alas. https://unix.stackexchange.com/a/567405/5132 https://

Some errors, just from the first few sections alone. From section 1: * "man hier" is out of date, alas. https://unix.stackexchange.com/a/567405/5132 https://unix.stackexchange.com/a/567405/5132 * If one is going to have a Linux/FreeBSD/Solaris split, one needs to apply it to section 1. "lsbrelease" is a Linux-based operating system only command. * Debian now includes /etc/os-release . Interestingly, so too does DragonFlyBSD (but not FreeBSD). * "last reboot" has been supposedly superseded in systemd operating systems, by "journalctl -b". * "atacontrol" was superseded by "camcontrol" in FreeBSD back in 2012. https://www.freebsd.org/releases/9.0R/relnotes-detailed.html#AEN1308 https://www.freebsd.org/releases/9.0R/relnotes-detailed.html... * Not even everyone has /var/log/messages any more, or /var/log/warn . Even Debian has, just last month, made the systemd journal its primary on-disc storage. * Use "vipw" to avoid having to remember to recompile master.passwd . It respects $EDITOR . * Most Linux operating systems do not use run levels at all now. http://jdebp.uk./FGA/run-levels-are-history.html http://jdebp.uk./FGA/run-levels-are-history.html In section 2: * The ps flags are 30 years out of date for the BSDs. BSD switched ps to use getopt() at the start of the 1990s, and they've officially started with a minus sign all of that time since. * The better trace program on FreeBSD, and the only one on OpenBSD, is the original BSD ktrace/kdump . In section 3: * FreeBSD partitioning is done with "gpart". I stopped there. There are probably some howlers under installation and shells, given how outdated some of the other stuff was. Debian and Ubuntu changed /bin/sh to the Debian Almquist shell a decade and a bit ago. FreeBSD replaced pkg with pkg-ng in version 9. These are two very common errors that I see.