/unix-cheat-sheet

Cheat sheet for managing various *nix (Linux, BSD, Illumos) systems.

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*nix Cheat Sheet

A cheat sheet for managing Linux, BSD, and illumos system

1. Table of Contents

  1. Table of Contents
  2. Service Management
  3. User Management
  4. Package Management
  5. Network Management
  6. Others
  7. Useful Resources

2. Service Management

Back to table of contents.

All of the commands involving the modification of a service state assume you are root or have proper rights either using sudo, doas (OpenBSD), or pfexec (illumos).

Majority of Linux distributions are using systemd.

BSDs are using the BSD style init. Aside from the command for FreeBSD and OpenBSD, you can also edit /etc/rc.conf or /etc/rc.conf.local.

illumos distributions are using the Service Management Facitly (smf).

Linux (systemd) FreeBSD OpenBSD illumos
Enable a service systemctl enable nginx sysrc nginx_enable=YES rcctl enable nginx svcadm enable nginx
Disable a service systemctl disable nginx sysrc nginx_enable=NO rcctl disable nginx svcadm disable nginx
Starting a service systemctl start nginx service nginx start rcctl start nginx svcadm enable nginx
Stopping a service systemctl stop nginx service nginx stop rcctl stop nginx svcadm disable nginx
List running services systemctl list-units - rcctl ls started svcs
List all services systemctl list-unit-files service -l rcctl ls all svcs -a
Check the status of a service systemctl status nginx service nginx status rcctl status nginx svcs -xv nginx

3. User Management

4. Package Management

Back to table of contents.

Linux distributions uses different package manager.

  1. apt and dpkg (Debian family)
  2. yum / dnf and rpm (Red Hat family)
  3. zypp and rpm (SUSE family) - Integrates with snapper and BTRFS to create system snapshots before and after using zypp.

BSDs also uses different package manager but they also have the ports system.

  1. pkgng (FreeBSD)
  2. pkgsrc (NetBSD)
  3. pkg (OpenBSD)

illumos distributions mostly uses the Image Packaging System (IPS).

  1. ips (OpenIndiana and OmniOS CE) - Integrates with beadm and ZFS to create boot environments after using ips.
  2. pkgsrc (SmartOS, also works with other illumos Distribution and the provide repositories for BSD, and Linux Distributions)
  3. zap (Tribblix)

The table will only include yum, apt, zypp, pkgng, pkgsrc, pkg, and ips. For NetBSD, you would need to install pkgin separately via pkg_add ${remote_url}/pkgin.

CentOS Debian OpenSUSE FreeBSD NetBSD OpenBSD OpenIndiana / OmniOS Community Edition
Installing a package yum install nginx apt-get install nginx zypper install nginx pkg install nginx pkgin install nginx pkg_add nginx pkg install nginx
Removing a package yum remove nginx apt-get remove nginx zypper remove pkg delete nginx pkgin remove nginx pkg_delete nginx pkg uninstall nginx
Update package cache yum check-update apt-get update zypper refresh pkg update pkgin update - pkg refresh
Updating installed packages yum update apt-get upgrade zyyper update pkg upgrade pkgin full-upgrade pkg_add -uU pkg update

5. Network Management

Tools

  • iproute2 - Linux (ifconfig can be used, but deprecated)
  • ifconfig - BSDs
  • crossbow - illumos (ifconfig can be used)

Notes

  • For Linux and BSDs, you would usually need to edit a file to make changes to interfaces persistent.
  • For illumos, using ipadm and dladm is enough
  • Syntax might be different across the BSDs
Linux BSDs illumos
List IP Address ip addr show ifconfig ipadm show-addr
List all interface ip link show ifconfig -a dladm show-link
Add an IP address ip addr add 192.168.0.1/24 dev eth0 ifconfig em0 inet 192.168.0.1 netmask 255.255.255.0 ipadm create-addr -T static -a 192.168.0.1 net0/v4
Set an interface up ip link set dev eth0 up ifconfig em0 up ipadm up-addr net0/v4
Set default route ip route add default via 192.168.0.254 route add default 192.168.0.254 route add default 192.168.0.254

6. Others

Other commands

Linux BSD Illumos
List open files lsof fstat pfiles <pid>
List block devices lsblk geom part list - FreeBSD, sysctl hw.disknames - OpenBSD format
Bind mounts mount --bind /mnt/a /mnt/b mount_nullfs /mnt/a /mnt/b mount -F lofs /mnt/a /mnt/b
Loop mounts mount -o loop disk.iso /mnt/disk mount -t cd9660 /dev/$(mdconfig -f disk.iso) /mnt/disk - FreeBSD, vnconfig /dev/vnd0 disk.iso; mount /dev/vnd0 /mnt/disk - OpenBSD mount -F hsfs -o ro $(lofiadm -a disk.iso) /mnt/disk

Kernel Modules

  • For NetBSD, you can only load a kernel module when running at kernel level -1 or 0 or during boot. Thus, it is recommended to load the module during boot.
  • OpenBSD does not support kernel modules.
Linux FreeBSD NetBSD OpenBSD illumos
List hardwares attached lspci pciconf -l pcictl list pcidump scanpci
Load kernel module modprobe module_name kldload module_name modload module_name - modload drv/module_name
Load kernel module at boot /etc/modules /boot/loader.conf /etc/modules.conf - /etc/system
List loaded kernel modules lsmod kldstat modstat - modinfo
Path of kernel modules /lib/modules/* /boot/kernel/* /stand/* - /kernel/*

Limiting resource and kernel tuning

  • For implementing resource limits, checkout the following path (and see their manpages)
System File Path
Linux /etc/security/limits.conf, systemd unit files, cgroups
BSD /etc/login.conf
Illumos /etc/project,/etc/system
  • For kernel tuning, checkout the following path (and see their manpages)
System File Path
Linux /etc/sysctl.conf
BSD /etc/sysctl.conf
Illumos /etc/system

FreeBSD Jails using NAT and PF

  1. Setup cloned interfaces.
cloned_interfaces="lo1"
ipv4_addrs_lo1="192.168.0.1-9/24"
  1. Configure PF.
ext_if=vtnet0          # Replace this with the interface with internet access
local_net=lo1:network  # This would be the network for you jails


# Outbound
nat on $ext_if from $local_net to any -> ($ext_if)  # Enable NAT
pass from $local_net to any keep state              # This will enable jails to access the internet

# Inbound
rdr on $ext_if proto tcp from any to ($ext_if) port 2222 -> $ip_in_jails port 22
pass in proto tcp to any port 2222
  1. Enable PF.
pf_enable="YES"
pf_flags=""
pf_rules="/etc/pf.conf"

gateway_enable="YES"

Illumos Zones using NAT and IPF

  1. Setup etherstub. This will act as the "virtual" switch.
[root@host ~]# dladm create-etherstub stub0
[root@host ~]# dladm create-vnic -l stub0 z1   # This will be the interface for your zone
[root@host ~]# dladm create-vnic -l stub0 g0   # This will be the interface for your host which will act as the gateway
  1. Assign IP address to g0.
[root@host ~] # ipadm create-if g0
[root@host ~] # ipadm create-addr -T static -a 192.168.0.1 g0/v4
  1. Create your zone.
[root@host ~] # zonecfg -z z1
z1: No such zone configured
Use 'create' to begin configuring a new zone.
zonecfg:z1> create
zonecfg:z1> set brand=sparse
zonecfg:z1> set ip-type=exclusive
zonecfg:z1> set zonepath=/zone/z1
zonecfg:z1> add net
zonecfg:z1:net> set physical=z1
zonecfg:z1:net> set allowed-address=192.168.0.2
zonecfg:z1:net> set defrouter=192.168.0.1
zonecfg:z1:net> end
zonecfg:z1> verify
zonecfg:z1> commit
zonecfg:z1> exit
  1. Configure ipf.conf and ipnat.conf
# ipf.conf

pass in on g0 from any to any
pass out on g0 from any to any

# ipnat.conf

map vioif0 192.168.0.0/24 -> 0/32 portmap tcp/udp auto
map vioif0 192.168.0.0/24 -> 0/32
  1. Install and start your zone.

Linux Containers using iptables and systemd-nspawn

  1. Create a base distribution (either using dnf, debootstrap, etc) and place it in a directory.
# Using debootstrap
[root@host ~] # mkdir debiansid && debootstrap --include=systemd-container sid debiansid
# Change initial root password
[root@host ~] # systemd-nspawn -D debiansid
[root@debiansid /] # passwd root
  1. Create bridge for networking
[root@host ~] # ip link add name virbr0 type bridge
[root@host ~] # ip addr add 192.168.0.1/24 dev virbr0
[root@host ~] # ip link set virbr0 up
  1. Enable NAT using iptables
[root@host ~] # iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
[root@host ~] # iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
[root@host ~] # iptables -A FORWARD -i virbr0 -o eth0 -j ACCEPT
  1. Start container using systemd-nspawn with network bridge.
[root@host ~] # systemd-nspawn -b --network-bridge=virbr0 -D debiansid
[root@debiansid /] # ip addr add 192.168.0.2 dev host0
[root@debiansid /] # ip link set host0 up
[root@debiansid /] # ip route add default via 192.168.0.1

7. Useful Resources

  1. Arch Wiki
  2. FreeBSD Handbook
  3. NetBSD Guide
  4. OpenBSD FAQ
  5. For illumos based distributions, Oracle SolarisTM documentation can still be used for majority of it's feature.
  6. The Linux-to-SmartOS Cheat Sheet - For Linux and Illumos