Gaurav Masand When a Linux machine has more than one network card, the first step is to confirm that the kernel can see each device. List network interfaces This shows interfaces such as eth0, eth1, ens33 or enp0s3, depending on the Linux distribution and naming scheme. Check PCI network hardware Check driver messages If a card is … Read more
Resizing a Linux filesystem can be useful when a partition or logical volume has become too small, but it should be treated as a careful maintenance task rather than a routine command. Check the current layout These commands help confirm the device name, mount point and filesystem type before making any change. Important safety notes … Read more
Bash scripts often need to read command-line arguments. For simple scripts, you can use positional parameters such as $1, $2 and $@. Simple positional arguments Loop through all arguments Basic option handling getopts is useful for small scripts that need flags such as -v or options with values such as -f file.txt.
aspell is a command-line spell checker. It is useful when editing plain text files, notes, documentation or scripts where you want a quick spelling pass without opening a full word processor. Check a text file This opens an interactive spelling session for the file. List possible misspellings This prints words that aspell thinks may be … Read more
Shell redirection operators control where command input and output go. They are useful for saving command output, appending logs, and passing one command’s output into another command. Write output to a file > writes output to a file. It replaces the existing file contents. Append output to a file >> appends output to the end … Read more
DNS search domains let a Linux system resolve short hostnames by automatically appending one or more domain names. Example If the search domain is example.com, a lookup for server1 may also try server1.example.com. Check resolver configuration You may see lines such as: Test name resolution On many modern distributions, /etc/resolv.conf may be managed by NetworkManager, … Read more
mpstat reports CPU usage statistics. It is useful when you want to see whether load is spread across processors or concentrated on one CPU. Show CPU statistics Refresh every few seconds Show each processor separately On many systems, mpstat is provided by the sysstat package.
A Linux system can act as a gateway for devices on a private LAN. Older documentation often called this IP masquerading; today the same idea is usually described as NAT or source NAT. What you need One interface connected to the upstream network or Internet. One interface connected to the private LAN. IP forwarding enabled. … Read more
The halt command is used to stop a Linux system. On modern Linux systems, systemctl poweroff or shutdown is usually preferred because it is clearer and works through systemd. Check the command first Modern equivalent Only run shutdown or power-off commands on a machine you are allowed to stop. Be especially careful on remote servers, … Read more
The host command is a simple DNS lookup tool. It is useful for checking whether a hostname resolves, which IP address it points to, or which mail servers are configured for a domain. Basic lookup Check mail servers Check name servers For deeper DNS troubleshooting, compare the result with dig and check whether the issue … Read more