Permissions

What a regular user can see

When running as a normal user, Linux restricts access to /proc/[pid]/ for processes owned by other users. Specifically:

• /proc/[pid]/cwd — permission denied for other users' processes
• /proc/[pid]/exe — permission denied for other users' processes

dir-cpu silently skips any process it cannot read. This means:

• You'll see your own processes accurately.
• System processes and other users' processes are invisible.

This is usually fine for development use — you typically want to see where your work is spending CPU.

Running with sudo for full system visibility

sudo dir-cpu

With root privileges, dir-cpu can read every process's cwd and exe, giving a complete picture of system-wide CPU consumption by directory.

WARNING

Running any monitoring tool as root has the usual caveats. dir-cpu does not write files or modify system state, but use sudo only when you need full visibility.

Why some directories still show 0%

Even with sudo, some processes may have no readable path:

• Kernel threads — they have no exe or meaningful cwd
• Processes in a different mount namespace or container
• Processes that exited between the two sampling snapshots

These are silently dropped from the output.

Containerized environments

Inside a Docker container, dir-cpu sees only the processes in the container's PID namespace. /proc is scoped to the container, so paths reflect the container's filesystem, not the host's.

To monitor from the host, run dir-cpu on the host (with sudo if needed), not inside the container.