Category: Tutorials

  • How To: List what Procs are using the Lib in Linux

    Find the Procs After upgrading an important package in Linux -or other Unix variant- that provides a library used by many other processes. Instead of restarting the server for the new lib to take effect, the procs can be restarted -or HUPed- individually. Before we begin, lsof needs to be installed. # RHEL / CentOS…

  • How To: Encrypt/Decrypt File with OpenSSL

    Encrypt/Decrypt File When security and integrity of a file is critical, such as with x509 certificates or other important documents, OpenSSL or other variant can be used to secure the file. With strong encryption and -hopefully- a strong password. OpenSSL is generally available on all UNIX variants, downloadable as an executable for Windows and is…

  • How To: Run a Command Quickly on Remote Server using SSH

    When working in a clustered Linux environment containing two or more servers, it is not uncommon to switch back and forth between the hosts. Even if it’s running one command. SSH is a powerful tool, it can do allot more than act as remote shell or tunnel traffic. One of those features is sending a…

  • How To: Linux – View Squid Proxy’s Active Cache Store

    Ever wanted to see whats going through Squid’s cache right at the moment? But get immediately discouraged with all the timestamps, SWAPOUT, RELEASE and other cache variables? I have a one-line for you! ~ # tail -f /var/log/squid/store.log|grep -oE ‘\b(http?)://[-A-Za-z0-9+&@#/%?=~_|!:,.;]*[-A-Za-z0-9+&@#/%=~_|]’ This will print out visited links that passes by squid in real time, it can…

  • How To: TOTP 2FA Linux SSH Using Google-Authenticator

    Using only a username and password for authentication is no longer secure. With user-database dumps reaching millions of exposed, albeit hashed and salted, passwords. Secure authentication should include not only something you know, but also something you have (in your pocket… always). There have been several OTP and general 2FA solutions for Linux. From SMS…