Why does the ps command truncate the command line to display only 4096 bytes? - Red Hat Customer Portal

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Issue

Some processes in system have very long command lines. When one tries to list the all parameters of those long parameters processes using ps aux or ps -ef command, only 4096 bytes of the command line are displayed and the rest is truncated.
Why does /proc/<pid>/cmdline truncate a command line longer than 4K?

Environment

Red Hat Enterprise Linux 4
Red Hat Enterprise Linux 5
Red Hat Enterprise Linux 6
Red Hat Enterprise Linux 7
procps
kernel

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