Documenting interesting stuff I learn about Linux/Unix

Configure alias

Alias can be configured through

alias <AN_ALIAS>=<THE_ACTUAL_COMMAND>

Example:

alias k=kubectl
  • note that this only configures alias for the current shell session.

To permanently configure an alias do:

echo "alias k='kubectl'" >> ~/.zshrc

Use alias to view all alias set

Locate files/directories

Files/directories could be located through:

locate <FILE_NAME>

Example:

locate hello_world.txt
  • note that locate depends on the database /var/db/locate.database which has to be initialized through:
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.locate.plist

Alternatively find command could also be used:

find <FILE_NAME>

Example:

sudo find  /opt -name caleston-code

Networking

DNS resolution

  • /etc/hosts

This is used for static hostname resolution where hostnames to IPs are mapped manually. The order of resolution takes precedence over DNS resolution; the system checks /etc/hosts before querying a DNS server, if a match is found, DNS server is not consulted.

Example:

127.0.0.1   localhost
192.168.1.10   myserver.example.com myserver
  • /etc/resolv.conf

This specifies DNS servers for resolving domain names into IP addresses. It contains configuration options and search domains.

Example:

nameserver 8.8.8.8
nameserver 8.8.4.4
search example.com

Here, nameserver specifies the DNS servers to query. search defines the fomain to append when trying to resolve a hostname. For example, if we try to resolve myserver, it will first attempt to resolve myserver.example.com