Linux client systems occupy an increasingly relevant position in security-conscious environments, from developer workstations to analyst machines handling sensitive data. Despite this, hardening guidance for Linux as a client operating system remains scarce: most available references are written with servers in mind, and the controls they prescribe frequently do not translate cleanly to a workstation context. This white paper addresses that gap. It provides a hardening baseline specifically for Linux client systems, developed and validated across a representative set of major distributions. The guide covers six domains, authentication and identity, network security, boot and integrity, operating system hardening, filesystem permissions, and application security and logging, and applies each control systematically, distinguishing mandatory requirements from optional recommendations using the terminology of RFC 2119. Settings that would severely impact usability without proportionate security benefit are excluded or explicitly marked. The goal is a hardened workstation that remains operationally viable, not locked down to the point of impracticality.