Blog

Practical guides on SSH, servers, databases and Mac utilities.

• Enable sysstat (sar) on Ubuntu, Debian and RHEL So You Have History Next Time
  How to install and enable sysstat so a Linux server keeps CPU, memory, load and disk history, and how to read yesterday's data with sar. Includes retention and verification.
• The SSH Config File on Mac: Aliases, Keys, Keychain and Per-Host Settings
  A practical guide to ~/.ssh/config on macOS: aliases, IdentityFile, storing key passphrases in the Keychain, wildcards, Include, keep-alives and connection reuse.
• SSH ProxyJump: Connect Through a Bastion Host with ~/.ssh/config
  How to reach servers behind a bastion (jump host) with one command: ProxyJump in ~/.ssh/config, multiple hops, scp and rsync, and how to debug it with ssh -G and -v.