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[rbdr/txt] / learning.md

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+2024-01-16: You don't actually need the users in unix in some situations, you can use an arbitrary number of the id and if the other system expects it, then it will work. In fact, you can "sudo" into that if runas_allow_unknown_id (then run sudo -u \#9999 <your_command>)

 2024-01-15: SELinux provides restrictions to files I wasn't aware of, and can prevent execution in some contexts. With eza you can view it with -Z.
 2024-01-14: On linux you can see logical volumes inside a partition with lsblk, they're shown as lvm. If you resize a partition, you still need to resize the lvm (eg. with `lvresize -l +100%FREE` to take all remaining free space), AND the filesystem (eg. using resize2fs). This is important eg when installing an OS from an image as you might not be using your whole disk.
 2024-01-15: SELinux provides restrictions to files I wasn't aware of, and can prevent execution in some contexts. With eza you can view it with -Z.
 2024-01-14: On linux you can see logical volumes inside a partition with lsblk, they're shown as lvm. If you resize a partition, you still need to resize the lvm (eg. with `lvresize -l +100%FREE` to take all remaining free space), AND the filesystem (eg. using resize2fs). This is important eg when installing an OS from an image as you might not be using your whole disk.

+2024-01-14: On fedora rather than ufw or nftables, you use firewalld. You can create services (eg. gopher with port tcp 70 goes in /etc/firewalld/services/gopher.xml), attach them to zones with `firewall-cmd --zone=<YOURZONE> --add-service=gopher --permanent`

 2024-01-14: User systemd files are expected in /etc/ and not /lib/
 2024-01-14: You can use @ and %i in systemd to have multiple instances (eg myfile@.service, and then executable=blabla %i) where %i will be what comes after @. (So in myfile@howdy, %i will expand to howdy)
 2024-01-13: PPP Connections stay alive in the old net router, so you don't need to run ATDTPPP again, but just the connection.
 2024-01-14: User systemd files are expected in /etc/ and not /lib/
 2024-01-14: You can use @ and %i in systemd to have multiple instances (eg myfile@.service, and then executable=blabla %i) where %i will be what comes after @. (So in myfile@howdy, %i will expand to howdy)
 2024-01-13: PPP Connections stay alive in the old net router, so you don't need to run ATDTPPP again, but just the connection.