Shell scripts are convenient, but they are a poor place to store passwords, API keys, or other long-lived secrets. Obfuscating or compiling a shell script does not provide strong secret protection because the secret must still become available to the running process. Prefer secret storage over script encryption Use a dedicated secret manager when one … Read more
The locale command shows the language, character encoding and regional settings used by the current shell session. Locale settings can affect sorting, dates, currency, messages and text handling. Show current locale Useful checks Locale mismatches are common causes of unexpected character display, sorting differences, or script output changes.
The sha1sum command calculates a SHA-1 checksum for a file. It can be useful for basic file comparison, but SHA-1 is no longer preferred for security-sensitive verification. Create a checksum Save and verify For modern downloads, use SHA-256 checksums when provided by the project or vendor.
The cksum command calculates a CRC checksum and file size. It is useful for simple integrity checks, especially when comparing whether two files are exactly the same. Basic use The output includes the checksum, byte count and file name. For download verification, prefer stronger checksums such as SHA-256 when available.
Java programs can be compiled and run from the Linux command line using the JDK tools javac and java. Check Java is installed If javac is missing, install a JDK package rather than only a runtime package. Compile a Java file This creates a compiled Hello.class file. Run the program Use the class name without … Read more
The factor command prints the prime factors of a number. It is a small utility, but useful for quick number checks from the command line. Examples The output shows the original number followed by its factors.
chmod changes file and directory permissions in Linux. It is useful when a script cannot execute, a file is too open, or a service needs access to a path. Make a script executable This adds execute permission for the file owner only. Common numeric permissions 644: owner can read/write, others can read 755: owner can … Read more
lsb_release shows Linux distribution information such as release name, version and codename. It is a quick way to confirm which distribution a server is running. Show all distribution details Show only the description If lsb_release is not installed, many modern systems also provide release information in /etc/os-release.
The logger command writes a message to the system log. It is useful in shell scripts when you want an action to leave a trace in the logs. Basic use You can add a tag so the message is easier to find later. Depending on the distribution, you can view these messages using journalctl or … Read more
Linux file permissions can reduce accidental changes, but for some files you may also want an extra layer of protection. On filesystems that support it, the immutable attribute can help. View file attributes Make a file immutable An immutable file cannot be modified, renamed or deleted until the attribute is removed. Remove the protection Use … Read more