Method of Running top Command in Batch Mode
- 2021-07-06 12:21:23
- OfStack
The top command is the best command everyone is using to monitor the performance of an Linux system. You probably already know most of the operations of the top command, except for a few, and if I'm right, batch mode is one of them.
Most scripters and developers know this, because this operation is mainly used to write scripts.
If you don't understand this, don't worry, we will introduce it here.
What is the batch mode of top commands
Batch mode allows you to send the output of the top command to other programs or files.
In this mode, the top command will not receive input and will continue to run until the number of iterations you specified with the-n option.
If you want to solve any performance problems on the Linux server, you need to understand the output of the top command correctly.
1) How to run the top command in batch mode
By default, the top command sorts the output according to the usage of CPU, so when you run the following command in batch mode, it will do the same and print the first 35 lines:
# top -bc | head -35
top - 06:41:14 up 8 days, 20:24, 1 user, load average: 0.87, 0.77, 0.81
Tasks: 139 total, 1 running, 136 sleeping, 0 stopped, 2 zombie
%Cpu(s): 0.0 us, 3.2 sy, 0.0 ni, 96.8 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 3880940 total, 1595932 free, 886736 used, 1398272 buff/cache
KiB Swap: 1048572 total, 514640 free, 533932 used. 2648472 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1 root 20 0 191144 2800 1596 S 0.0 0.1 5:43.63 /usr/lib/systemd/systemd --switched-root --system --deserialize 22
2 root 20 0 0 0 0 S 0.0 0.0 0:00.32 [kthreadd]
3 root 20 0 0 0 0 S 0.0 0.0 0:28.10 [ksoftirqd/0]
5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [kworker/0:0H]
7 root rt 0 0 0 0 S 0.0 0.0 0:33.96 [migration/0]
8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 [rcu_bh]
9 root 20 0 0 0 0 S 0.0 0.0 63:05.12 [rcu_sched]
10 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [lru-add-drain]
11 root rt 0 0 0 0 S 0.0 0.0 0:08.79 [watchdog/0]
12 root rt 0 0 0 0 S 0.0 0.0 0:08.82 [watchdog/1]
13 root rt 0 0 0 0 S 0.0 0.0 0:44.27 [migration/1]
14 root 20 0 0 0 0 S 0.0 0.0 1:22.45 [ksoftirqd/1]
16 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [kworker/1:0H]
18 root 20 0 0 0 0 S 0.0 0.0 0:00.01 [kdevtmpfs]
19 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [netns]
20 root 20 0 0 0 0 S 0.0 0.0 0:01.35 [khungtaskd]
21 root 0 -20 0 0 0 S 0.0 0.0 0:00.02 [writeback]
22 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [kintegrityd]
23 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [bioset]
24 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [kblockd]
25 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [md]
26 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [edac-poller]
33 root 20 0 0 0 0 S 0.0 0.0 1:19.07 [kswapd0]
34 root 25 5 0 0 0 S 0.0 0.0 0:00.00 [ksmd]
35 root 39 19 0 0 0 S 0.0 0.0 0:12.80 [khugepaged]
36 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [crypto]
44 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [kthrotld]
46 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [kmpath_rdacd]
2) How to run the top command in batch mode and sort the results by memory usage
Run the following command in batch mode to sort the results by memory usage:
# top -bc -o +%MEM | head -n 20
top - 06:42:00 up 8 days, 20:25, 1 user, load average: 0.66, 0.74, 0.80
Tasks: 146 total, 1 running, 145 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 3880940 total, 1422044 free, 1059176 used, 1399720 buff/cache
KiB Swap: 1048572 total, 514640 free, 533932 used. 2475984 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
18105 mysql 20 0 1453900 156096 8816 S 0.0 4.0 2:12.98 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
1841 root 20 0 228980 107036 5360 S 0.0 2.8 0:05.56 /usr/local/cpanel/3rdparty/perl/528/bin/perl -T -w /usr/local/cpanel/3rdparty/bin/spamd --max-children=3 --max-spare=1 --allowed-ips=127.0.0.+
4301 root 20 0 230208 104608 1816 S 0.0 2.7 0:03.77 spamd child
8139 nobody 20 0 257000 27108 3408 S 0.0 0.7 0:00.04 /usr/sbin/httpd -k start
7961 nobody 20 0 256988 26912 3160 S 0.0 0.7 0:00.05 /usr/sbin/httpd -k start
8190 nobody 20 0 256976 26812 3140 S 0.0 0.7 0:00.05 /usr/sbin/httpd -k start
8353 nobody 20 0 256976 26812 3144 S 0.0 0.7 0:00.04 /usr/sbin/httpd -k start
8629 nobody 20 0 256856 26736 3108 S 0.0 0.7 0:00.02 /usr/sbin/httpd -k start
8636 nobody 20 0 256856 26712 3100 S 0.0 0.7 0:00.03 /usr/sbin/httpd -k start
8611 nobody 20 0 256844 25764 2228 S 0.0 0.7 0:00.01 /usr/sbin/httpd -k start
8451 nobody 20 0 256844 25760 2220 S 0.0 0.7 0:00.04 /usr/sbin/httpd -k start
8610 nobody 20 0 256844 25748 2224 S 0.0 0.7 0:00.01 /usr/sbin/httpd -k start
8632 nobody 20 0 256844 25744 2216 S 0.0 0.7 0:00.03 /usr/sbin/httpd -k startDetails of the above command:
-b: Batch mode option
-c: Print the absolute path of a running process
-o: Specifies the fields to sort
head: Part 1 of the output file
-n: Print front n line
3) How to run the top command in batch mode and sort the results by the specified user process
If you want to sort the results by the specified user process, run the following command:
# top -bc -u mysql | head -n 10
top - 06:44:58 up 8 days, 20:27, 1 user, load average: 0.99, 0.87, 0.84
Tasks: 140 total, 1 running, 137 sleeping, 0 stopped, 2 zombie
%Cpu(s): 13.3 us, 3.3 sy, 0.0 ni, 83.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 3880940 total, 1589832 free, 885648 used, 1405460 buff/cache
KiB Swap: 1048572 total, 514640 free, 533932 used. 2649412 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
18105 mysql 20 0 1453900 156888 8816 S 0.0 4.0 2:16.42 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
4) How to run the top command in batch mode and sort by processing time
In batch mode, use the following top command to sort the results by processing time. This shows the total CPU time that the task has used since it started.
But if you want to check how long a process has been running on Linux, please see the following article:
Five Methods of Checking Process Running Time in Linux
# top -bc -o TIME+ | head -n 20
top - 06:45:56 up 8 days, 20:28, 1 user, load average: 0.56, 0.77, 0.81
Tasks: 148 total, 1 running, 146 sleeping, 0 stopped, 1 zombie
%Cpu(s): 0.0 us, 3.1 sy, 0.0 ni, 96.9 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 3880940 total, 1378664 free, 1094876 used, 1407400 buff/cache
KiB Swap: 1048572 total, 514640 free, 533932 used. 2440332 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
9 root 20 0 0 0 0 S 0.0 0.0 63:05.70 [rcu_sched]
272 root 20 0 0 0 0 S 0.0 0.0 16:12.13 [xfsaild/vda1]
3882 root 20 0 229832 6212 1220 S 0.0 0.2 9:00.84 /usr/sbin/httpd -k start
1 root 20 0 191144 2800 1596 S 0.0 0.1 5:43.75 /usr/lib/systemd/systemd --switched-root --system --deserialize 22
3761 root 20 0 68784 9820 2048 S 0.0 0.3 5:09.67 tailwatchd
3529 root 20 0 404380 3472 2604 S 0.0 0.1 3:24.98 /usr/sbin/rsyslogd -n
3520 root 20 0 574208 572 164 S 0.0 0.0 3:07.74 /usr/bin/python2 -Es /usr/sbin/tuned -l -P
444 dbus 20 0 58444 1144 612 S 0.0 0.0 2:23.90 /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation
18105 mysql 20 0 1453900 157152 8816 S 0.0 4.0 2:17.29 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid
249 root 0 -20 0 0 0 S 0.0 0.0 1:28.83 [kworker/0:1H]
14 root 20 0 0 0 0 S 0.0 0.0 1:22.46 [ksoftirqd/1]
33 root 20 0 0 0 0 S 0.0 0.0 1:19.07 [kswapd0]
342 root 20 0 39472 2940 2752 S 0.0 0.1 1:18.17 /usr/lib/systemd/systemd-journald
5) How to run the top command in batch mode and save the results to a file
If you want to share the output of the top command for problem solving purposes, use the following command to redirect the output to a file:
# top -bc | head -35 > top-report.txt
# cat top-report.txt
top - 06:47:11 up 8 days, 20:30, 1 user, load average: 0.67, 0.77, 0.81
Tasks: 133 total, 4 running, 129 sleeping, 0 stopped, 0 zombie
%Cpu(s): 59.4 us, 12.5 sy, 0.0 ni, 28.1 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 3880940 total, 1596268 free, 843284 used, 1441388 buff/cache
KiB Swap: 1048572 total, 514640 free, 533932 used. 2659084 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
9686 daygeekc 20 0 406132 62184 43448 R 94.1 1.6 0:00.34 /opt/cpanel/ea-php56/root/usr/bin/php-cgi
9689 nobody 20 0 256588 24428 1184 S 5.9 0.6 0:00.01 /usr/sbin/httpd -k start
1 root 20 0 191144 2800 1596 S 0.0 0.1 5:43.79 /usr/lib/systemd/systemd --switched-root --system --deserialize 22
2 root 20 0 0 0 0 S 0.0 0.0 0:00.32 [kthreadd]
3 root 20 0 0 0 0 S 0.0 0.0 0:28.11 [ksoftirqd/0]
5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [kworker/0:0H]
7 root rt 0 0 0 0 S 0.0 0.0 0:33.96 [migration/0]
8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 [rcu_bh]
9 root 20 0 0 0 0 R 0.0 0.0 63:05.82 [rcu_sched]
10 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [lru-add-drain]
11 root rt 0 0 0 0 S 0.0 0.0 0:08.79 [watchdog/0]
12 root rt 0 0 0 0 S 0.0 0.0 0:08.82 [watchdog/1]
13 root rt 0 0 0 0 S 0.0 0.0 0:44.28 [migration/1]
14 root 20 0 0 0 0 S 0.0 0.0 1:22.46 [ksoftirqd/1]
16 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [kworker/1:0H]
18 root 20 0 0 0 0 S 0.0 0.0 0:00.01 [kdevtmpfs]
19 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [netns]
20 root 20 0 0 0 0 S 0.0 0.0 0:01.35 [khungtaskd]
21 root 0 -20 0 0 0 S 0.0 0.0 0:00.02 [writeback]
22 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [kintegrityd]
23 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [bioset]
24 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [kblockd]
25 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [md]
26 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [edac-poller]
33 root 20 0 0 0 0 S 0.0 0.0 1:19.07 [kswapd0]
34 root 25 5 0 0 0 S 0.0 0.0 0:00.00 [ksmd]
35 root 39 19 0 0 0 S 0.0 0.0 0:12.80 [khugepaged]
36 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 [crypto]
How to sort results by specified fields
In the latest version of the top command, press the f key to enter the field management interface.
To sort with the new field, use the up/down arrow to select the correct option, and then press the s key to sort. Finally, press q to exit this window.
Fields Management for window 1:Def, whose current sort field is %CPU
Navigate with Up/Dn, Right selects for move then or Left commits,
'd' or toggles display, 's' sets sort. Use 'q' or to end!
PID = Process Id nsUTS = UTS namespace Inode
USER = Effective User Name LXC = LXC container name
PR = Priority RSan = RES Anonymous (KiB)
NI = Nice Value RSfd = RES File-based (KiB)
VIRT = Virtual Image (KiB) RSlk = RES Locked (KiB)
RES = Resident Size (KiB) RSsh = RES Shared (KiB)
SHR = Shared Memory (KiB) CGNAME = Control Group name
S = Process Status NU = Last Used NUMA node
%CPU = CPU Usage
%MEM = Memory Usage (RES)
TIME+ = CPU Time, hundredths
COMMAND = Command Name/Line
PPID = Parent Process pid
UID = Effective User Id
RUID = Real User Id
RUSER = Real User Name
SUID = Saved User Id
SUSER = Saved User Name
GID = Group Id
GROUP = Group Name
PGRP = Process Group Id
TTY = Controlling Tty
TPGID = Tty Process Grp Id
SID = Session Id
nTH = Number of Threads
P = Last Used Cpu (SMP)
TIME = CPU Time
SWAP = Swapped Size (KiB)
CODE = Code Size (KiB)
DATA = Data+Stack (KiB)
nMaj = Major Page Faults
nMin = Minor Page Faults
nDRT = Dirty Pages Count
WCHAN = Sleeping in Function
Flags = Task Flags
CGROUPS = Control Groups
SUPGIDS = Supp Groups IDs
SUPGRPS = Supp Groups Names
TGID = Thread Group Id
OOMa = OOMEM Adjustment
OOMs = OOMEM Score current
ENVIRON = Environment vars
vMj = Major Faults delta
vMn = Minor Faults delta
USED = Res+Swap Size (KiB)
nsIPC = IPC namespace Inode
nsMNT = MNT namespace Inode
nsNET = NET namespace Inode
nsPID = PID namespace Inode
nsUSER = USER namespace InodeFor older versions of the top command, press shift+f or shift+o to enter the field management interface to sort.
To sort with the new field, select the corresponding sort field letter, and then press Enter to sort.
Current Sort Field: N for window 1:Def
Select sort field via field letter, type any other key to return
a: PID = Process Id
b: PPID = Parent Process Pid
c: RUSER = Real user name
d: UID = User Id
e: USER = User Name
f: GROUP = Group Name
g: TTY = Controlling Tty
h: PR = Priority
i: NI = Nice value
j: P = Last used cpu (SMP)
k: %CPU = CPU usage
l: TIME = CPU Time
m: TIME+ = CPU Time, hundredths
* N: %MEM = Memory usage (RES)
o: VIRT = Virtual Image (kb)
p: SWAP = Swapped size (kb)
q: RES = Resident size (kb)
r: CODE = Code size (kb)
s: DATA = Data+Stack size (kb)
t: SHR = Shared Mem size (kb)
u: nFLT = Page Fault count
v: nDRT = Dirty Pages count
w: S = Process Status
x: COMMAND = Command name/line
y: WCHAN = Sleeping in Function
z: Flags = Task Flags
Note1:
If a selected sort field can't be
shown due to screen width or your
field order, the '<' and '>' keys
will be unavailable until a field
within viewable range is chosen.
Note2:
Field sorting uses internal values,
not those in column display. Thus,
the TTY & WCHAN fields will violate
strict ASCII collating sequence.
(shame on you if WCHAN is chosen)Summarize