May 26th, 2009
Changing Virtual Files
Changing Virtual Files
As a general rule, most virtual files within the /proc/ directory are read-only. However, some can be used to adjust settings in the kernel. This is especially true for files in the /proc/sys/ subdirectory.
To change the value of a virtual file, use the echo command and a greater than symbol (>) to redirect the new value to the file. For example, to change the hostname on the fly, type:
Other files act as binary or Boolean switches. Typing cat /proc/sys/net/ipv4/ip_forward returns either a 0 or a 1. A 0 indicates that the kernel is not forwarding network packets. Using the echo command to change the value of the ip_forward file to 1 immediately turns packet forwarding on.