man -k command doesn't work

[RBahra]

I am studying RH134 (Red Hat System Administration II) and I am upto chapter about Managing Temproray Files. In this topic @ricardodacosta shows an example "man -k systemd | grep 5", when he runs this command. It shows all systemd man pages (5), however when I run this command on my rhel9 it gives error "systemd: nothing appropriate". I am confused and I have spending so much time to figure it out whats wrong with my system. Do I need to do update or upgrade?

Any suggestions would be really appericate and help me to resolve this issue, I am just losing my mind on this

[ARoumiantsev · Accepted solution]

Hi @RBahra 

"man -k ..." is working according index database caches. mandb command is used to initialise or manually update it. Please, run mandb under superuser account before your example "man -k systemd | grep 5"  

Good luck

[Chetan_Tiwary_]

@RBahra yup sudo mandb is the trick!