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Linux Command - htop

The Linux htop command is a process viewer similar to top.

Command Line Options

-d Delay between updates, in tenths of a second. rounded up to 1/10 and down to 10 secs
-C monochrome mode
-F=FILTER filter stuff
-h help
-p=PID,PID… Show only the given PIDs
-s COLUMN Sort by this column
-s help show a column list
-u Show only the processes of a given user
-U Do not use unicode but ASCII characters for graph meters
-M Disable support of mouse control
–readonly Disable all system and process changing features
-V Output version information and exit
-t Show processes in tree view.
-H Highlight new and old processes

Interactive Commands

Tab, Shift-Tab Select the next / the previous screen tab to display.  
Up, Alt-k Select (highlight) the previous process in the process list.  
Down, Alt-j Select (highlight) the next process in the process list.  
Left, Alt-h Scroll the process list left.  
Right, Alt-l Scroll the process list right.  
PgUp, PgDn Scroll the process list up or down one window.  
Home Scroll to the top of the process list and select the first process.  
End Scroll to the bottom of the process list and select the last process.  
Ctrl-A, ^ Scroll left to the beginning of the process entry (i.e. beginning of line).  
Ctrl-E, $ Scroll right to the end of the process entry (i.e. end of line).  
Space Tag or untag a process  
c Tag the current process and its children  
U Untag all processes  
s Trace process system calls: if strace(1) is installed, pressing this key will attach it to the currently selected process, presenting a live update of system calls issued by the process.  
l Display open files for a process: if lsof(1) is installed, pressing this key will display the list of file descriptors opened by the process  
w Display the command line of the selected process in a separate screen  
x Display the active file locks of the selected process in a separate screen.  
F1, h, ? Go to the help screen  
F2, S Go to the setup screen  
F3, / Search by command lines, highlight while typing, F3 for next, Shift-F3 for previous  
F4, \ Filter by command lines, case-insensitive, no regex, separate terms with “ ”,
F5, t Tree view  
F6, <, > Selects a field for sorting  
F7, ] Increase the selected process’s priority (subtract from ‘nice’ value).  
F8, [ Decrease the selected process’s priority (add to ‘nice’ value)  
shift - F7, } Increase the selected process’s autogroup priority (subtract from autogroup ‘nice’ value)  
shift - F8, } Decrease the selected process’s autogroup priority (add to autogroup ‘nice’ value)  
F9, K “Kill” process: sends a signal which is selected in a menu  
F10, q quit  
I Invert the sort order  
+, -, * When in tree view mode, expand or collapse subtree.  
a (on multiprocessor machines) Set CPU affinity: mark which CPUs a process is allowed to use.  
u Show only processes owned by a specified user.  
N Sort by PID.  
M Sort by memory usage (top compatibility key).  
P Sort by processor usage (top compatibility key).  
T Sort by time (top compatibility key).  
F “Follow” process, selection bar stays on process when proc moves  
K Hide kernel threads  
H Hide user threads  
p Show full paths to running programs  
Z Pause/resume process updates.  
m Merge exe, comm and cmdline, where applicable.  
Ctrl-L Refresh: redraw screen and recalculate values.  
Numbers PID search: type in process ID and the selection highlight will be moved to it.  


Command The full command line of the process  
COMM The command name of the process  
EXE The abbreviated basename of the executable of the process  
PID The process ID  
STATE (S) Process state: S - sleeping,I - idle,R - running,D - disk sleep,Z - zombie, T - traced or suspended, W - paging  
PPID The parent process ID.  
PGRP The process’s group ID.  
SESSION (SID) The process’s session ID.  
TTY The controlling terminal of the process.  
TPGID The process ID of the foreground process group of the controlling terminal.  
MINFLT The number of page faults happening in the main memory.  
CMINFLT The number of minor faults for the process’s waited-for children  
MAJFLT The number of page faults happening out of the main memory.  
CMAJFLT The number of major faults for the process’s waited-for children  
UTIME (UTIME+) The user CPU time.  
STIME (STIME+) The system CPU time.  
CUTIME (CUTIME+) The children’s user CPU time.  
CSTIME (CSTIME+) The children’s system CPU time.  
PRIORITY (PRI) The kernel’s internal priority for proc  
NICE (NI) The nice value of a process, from 19 (low) to -20 (high).  
STARTTIME (START) The time the process was started.  
PROCESSOR (CPU) The ID of the CPU the process last executed on.  
M_VIRT (VIRT) The size of the virtual memory of the process.  
M_RESIDENT (RES) The resident set size (text + data + stack) of the process ( proc’s used physical mem)  
M_SHARE (SHR) The size of the process’s shared pages.  
M_TRS (CODE) The text resident set size of the process (process’s executable instructions).  
  M_DRS (DATA) The data resident set size (data + stack) of the process
M_LRS (LIB) The library size of the process.  
M_SWAP (SWAP) The size of the process’s swapped pages.  
M_PSS (PSS) The proportional set size.  
M_M_PSSWP (PSSWP) The proportional swap share of this mapping.  
ST_UID (UID) The user ID of the process owner.  
PERCENT_CPU (CPU%) The percentage of the CPU time that the process is currently using. T  
PERCENT_NORM_CPU (NCPU%) The percentage of the CPU time, normalized by CPU count.  
PERCENT_MEM (MEM%) The percentage of memory the process is currently using  
USER The username of the process owner, or the user ID  
TIME (TIME+) The time, measured in clock ticks that the process has spent in user and system time  
NLWP The number of Light-Weight Processes (=threads) in the process.  
TGID The thread group ID.  
CTID OpenVZ container ID, a.k.a virtual environment ID.  
VPID OpenVZ process ID.  
VXID VServer process ID.  
RCHAR (RD_CHAR) The number of bytes the process has read.  
WCHAR (WR_CHAR) The number of bytes the process has written.  
SYSCR (RD_SYSC) The number of read(2) syscalls for the process.  
SYSCW (WR_SYSC) The number of write(2) syscalls for the process.  
RBYTES (IO_RBYTES) Bytes of read(2) I/O for the process.  
WBYTES (IO_WBYTES) Bytes of write(2) I/O for the process.  
CNCLWB (IO_CANCEL) Bytes of cancelled write(2) I/O.  
IO_READ_RATE (DISK READ) The I/O rate of read(2) in bytes per second, for the process.  
IO_WRITE_RATE (DISK WRITE) The I/O rate of write(2) in bytes per second, for the process.  
IO_RATE (DISK R/W) The I/O rate, IO_READ_RATE + IO_WRITE_RATE (see above).  
CGROUP Which cgroup the process is in. For a shortened view see the CCGROUP column below.  
CCGROUP Shortened view of the cgroup name that the process is in.  
OOM OOM killer score.  
CTXT Incremental sum of voluntary and nonvoluntary context switches.  
IO_PRIORITY (IO) The I/O sched class and priority: R - Realtime, B - Best-effort, id - Idle  
PERCENT_CPU_DELAY (CPUD%) The percentage of time spent waiting for a CPU (while runnable).  
PERCENT_IO_DELAY (IOD%) The percentage of time spent waiting for the completion of synchronous block I/O.  
PERCENT_SWAP_DELAY (SWAPD%) The percentage of time spent swapping in pages.  
AGRP The autogroup identifier for the process.  
ANI The autogroup nice value for the process autogroup.  

Config files

~/.config/htop/htoprc user config, don’t hand edit
/etc/htoprc default system config, read if user config doesn’t exist
$HTOPRC override config location with this