====== htop ======

  * [[Linux Memory and Processes]]

htop is an alternative display for top, showing system processes.

By default, htop will order the processes by PID.

=== FreeBSD ===

<code>
echo linproc /compat/linux/proc linprocfs rw 0 0 >> /etc/fstab
mkdir -p /usr/compat/linux/proc
ln -s /usr/compat /compat
mount linproc
</code>

=== Examples ===

Show processes being run by user mysql:

<code>
htop -u mysql
</code>

Display threads for user apache, sorted by how long they have been running:

<code>
htop -u apache --sort-key TIME
</code>

See how much memory apache threads are really using, highest values first:

<code>
htop -u apache --sort-key M_RESIDENT
</code>

Watching the system to see what programs are using the most memory, the highest percentage of CPU, the highest percentage of memory, and then running the longest time:

<code>
htop -u apache --sort-key M_RESIDENT
htop -u apache --sort-key PERCENT_CPU
htop -u apache --sort-key PERCENT_MEM
htop -u apache --sort-key TIME
</code>

=== Display Values ===

The default values displayed are:

  * PID
  * USER
  * PRIORITY
  * NICE
  * M_SIZE
  * M_RESIDENT
  * M_SHARE
  * STATE
  * PERCENT_CPU
  * PERCENT_MEM
  * TIME
  * Command

=== Gotchas ===

htop's argument for sorting by keys is not consistent across versions, despite what the --help output may say.  To sort by a key, use ''--sort-key <value>'', which will work everywhere.