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Linux Command – top ใช้ในการจัดเรียงอันดับแสดงการทำงานของ process

คำสั่ง

top

$ top

top - 10:26:25 up 3 days, 13 min, 1 user, load average: 0.10, 0.13, 0.12
Tasks: 204 total, 1 running, 182 sleeping, 21 stopped, 0 zombie
%Cpu(s): 1.0 us, 0.2 sy, 0.0 ni, 97.3 id, 1.4 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 3969412 total, 1082728 free, 2139796 used, 746888 buff/cache
KiB Swap: 1756156 total, 970724 free, 785432 used. 1487604 avail Mem 

 PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 
 2416 root 20 0 40520 3812 3208 R 6.2 0.1 0:00.01 top 
 1 root 20 0 37752 4880 3268 S 0.0 0.1 0:12.61 systemd 
 2 root 20 0 0 0 0 S 0.0 0.0 0:00.02 kthreadd 
 3 root 20 0 0 0 0 S 0.0 0.0 0:00.68 ksoftirqd/0 
 5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H 
 7 root 20 0 0 0 0 S 0.0 0.0 1:04.31 rcu_sched 
 8 root 20 0 0 0 0 S 0.0 0.0 0:00.00 rcu_bh 
 9 root rt 0 0 0 0 S 0.0 0.0 0:00.16 migration/0

PID – Process ID
USER – User ที่ใช้งาน process
%CPU – CPU usage
%MEM – Memory usage
COMMAND – คำสั่งที่ process ทำงาน

โครงสร้างคำสั่ง

 top -hv|-bcHiOSs -d secs -n max -u|U user -p pid -o fld -w [cols]

รายละเอียด

เป็นคำสั่งที่ใช้ในการจัดเรียงอันดับแสดงการทำงานของ process

Option

 -hv|-bcHiOSs -d secs -n max -u|U user -p pid -o fld -w [cols]

 The typically mandatory switch ('-') and even whitespace are completely optional.

 -h | -v :Help/Version
 Show library version and the usage prompt, then quit.

 -b :Batch-mode operation
 Starts top in Batch mode, which could be useful for sending output from top to other programs or to a file. In this mode, top will not accept input and runs until the itera‐
 tions limit you've set with the `-n' command-line option or until killed.

 -c :Command-line/Program-name toggle
 Starts top with the last remembered `c' state reversed. Thus, if top was displaying command lines, now that field will show program names, and visa versa. See the `c' inter‐
 active command for additional information.

 -d :Delay-time interval as: -d ss.t (secs.tenths)
 Specifies the delay between screen updates, and overrides the corresponding value in one's personal configuration file or the startup default. Later this can be changed with
 the `d' or `s' interactive commands.

 Fractional seconds are honored, but a negative number is not allowed. In all cases, however, such changes are prohibited if top is running in Secure mode, except for root
 (unless the `s' command-line option was used). For additional information on Secure mode see topic 6a. SYSTEM Configuration File.

 -H :Threads-mode operation
 Instructs top to display individual threads. Without this command-line option a summation of all threads in each process is shown. Later this can be changed with the `H'
 interactive command.

 -i :Idle-process toggle
 Starts top with the last remembered `i' state reversed. When this toggle is Off, tasks that have not used any CPU since the last update will not be displayed. For additional
 information regarding this toggle see topic 4c. TASK AREA Commands, SIZE.

 -n :Number-of-iterations limit as: -n number
 Specifies the maximum number of iterations, or frames, top should produce before ending.

 -o :Override-sort-field as: -o fieldname
 Specifies the name of the field on which tasks will be sorted, independent of what is reflected in the configuration file. You can prepend a `+' or `-' to the field name to
 also override the sort direction. A leading `+' will force sorting high to low, whereas a `-' will ensure a low to high ordering.

 This option exists primarily to support automated/scripted batch mode operation.

 -O :Output-field-names
 This option acts as a form of help for the above -o option. It will cause top to print each of the available field names on a separate line, then quit. Such names are sub‐
 ject to nls translation.

 -p :Monitor-PIDs mode as: -pN1 -pN2 ... or -pN1,N2,N3 ...
 Monitor only processes with specified process IDs. This option can be given up to 20 times, or you can provide a comma delimited list with up to 20 pids. Co-mingling both
 approaches is permitted.

 A pid value of zero will be treated as the process id of the top program itself once it is running.

 This is a command-line option only and should you wish to return to normal operation, it is not necessary to quit and restart top -- just issue any of these interactive com‐
 mands: `=', `u' or `U'.

 The `p', `u' and `U' command-line options are mutually exclusive.

 -s :Secure-mode operation
 Starts top with secure mode forced, even for root. This mode is far better controlled through the system configuration file (see topic 6. FILES).

 -S :Cumulative-time toggle
 Starts top with the last remembered `S' state reversed. When Cumulative time mode is On, each process is listed with the cpu time that it and its dead children have used.
 See the `S' interactive command for additional information regarding this mode.

 -u | -U :User-filter-mode as: -u | -U number or name
 Display only processes with a user id or user name matching that given. The `-u' option matches on effective user whereas the `-U' option matches on any user (real, effec‐
 tive, saved, or filesystem).

 Prepending an exclamation point ('!') to the user id or name instructs top to display only processes with users not matching the one provided.

 The `p', `u' and `U' command-line options are mutually exclusive.

 -w :Output-width-override as: -w [ number ]
 In Batch mode, when used without an argument top will format output using the COLUMNS= and LINES= environment variables, if set. Otherwise, width will be fixed at the maximum
 512 columns. With an argument, output width can be decreased or increased (up to 512) but the number of rows is considered unlimited.

 In normal display mode, when used without an argument top will attempt to format output using the COLUMNS= and LINES= environment variables, if set. With an argument, output
 width can only be decreased, not increased. Whether using environment variables or an argument with -w, when not in Batch mode actual terminal dimensions can never be
 exceeded.

 Note: Without the use of this command-line option, output width is always based on the terminal at which top was invoked whether or not in Batch mode.

กลุ่มคำสั่ง

free(1), ps(1), uptime(1), atop(1), slabtop(1), vmstat(8), w(1)

Reference:

คำสั่ง Unix – Linux Command

Linux, Unix

Author: Suphakit Annoppornchai

Credit: https://saixiii.com