Where can I find the source code for the free command on Linux?
The source code for the
free commands (and many more, like
sysctl) can be found in procps-ng:
procps is a set of command line and full-screen utilities that provide information out of the pseudo-filesystem most commonly located at /proc.
This pseudo-filesystem provides a simple interface to the kernel data structures. The programs of procps generally concentrate on the structures that describe the processess running on the system.
The following programs are found in procps:
free - Report the amount of free and used memory in the system kill - Send a signal to a process based on PID pgrep - List processes based on name or other attributes pkill - Send a signal to a process based on name or other attributes pmap - Report memory map of a process ps - Report information of processes pwdx - Report current directory of a process skill - Obsolete version of pgrep/pkill slabtop - Display kernel slab cache information in real time snice - Renice a process sysctl - Read or Write kernel parameters at run-time tload - Graphical representation of system load average top - Dynamic real-time view of running processes uptime - Display how long the system has been running vmstat - Report virtual memory statistics w - Report logged in users and what they are doing watch - Execute a program periodically, showing output fullscreen