The explainshell output is actually largely wrong here. For historical reasons, GNU ps has two completely different sets of flags depending on whether you use

The explainshell output is actually largely wrong here. For historical reasons, GNU ps has two completely different sets of flags depending on whether you use a dash (ps -abcd) or not (ps abcd). The man page documents both sets, but explainshell is getting confused and showing a mix of dash versions and non-dash versions. For example, it shows the documentation for '-f' ("full-format listing"), but it should be showing the documentation for 'f' ("ASCII art process hierarchy (forest)"). (I considered filing a bug report, but there is one already: https://github.com/idank/explainshell/issues/214 https://github.com/idank/explainshell/issues/214)