How to reduce and/or add more columns or fields to top command in Linux (swap, memory, etc)

I have already written an article explaining every field in the top command

10 examples to help you understand top command usage in Linux

In this article I will show you the steps using which you can control the list of columns you would like to see with the top command.

By default we see the below columns when top is executed without any arguments

11584 root      20   0  116376   1012    844 R 99.9  0.0  18716:08 agetty
    1 root      20   0  133792   4156   2552 S  0.0  0.0   0:38.09 systemd
    2 root      20   0       0      0      0 S  0.0  0.0   0:00.04 kthreadd
    3 root      20   0       0      0      0 S  0.0  0.0   0:01.31 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   0:00.00 migration/0

Adding a new column

Here I would like to add one more field to monitor the "swap" memory usage per process
To do this, press "f" which will show you below list of options

Here if you see some of the options are bright white, these are the fields which are currently enabled by default, to which now we would like to add "SWAP" details

so navigate to the row which contains SWAP as shown below

and press "space" bar to select the highlighted option. Once you hit "space" bar, the highlighted option should turn to bright white color similar to other default options.

To go back to the home screen of top, press "Esc"
So now as you can see, a new column with "SWAP" has appeared at the last column

Similarly you can add any other column from the list of fields

Removing an existing column

To reduce or remove a column also similar steps can be followed as explained above

Press "f" to go to the list of fields and navigate to the option which you would like to remove from the default top home screen

Press "space" bar to un-select the field, by doing this the colour of the field would turn back to normal white colour similar to all other disabled sections as shown below, here I disabled "RES" memory column, press "Esc" to go back

So now the same has vanished from top home screen.

Save the changes permanently

To save the changes what you have made, so that the same is active when you execute top next time
press "Shift+w"

Once you press the same, you should see the above line as shown in the screenshot. The changes will be saved under your home folder using which top was executed

Below is the content of my /root/.toprc

top's Config File (Linux processes with windows)
Id:i, Mode_altscr=0, Mode_irixps=1, Delay_time=3.0, Curwin=0
Def     fieldscur=¥¨³´»=ÃÃ
efghij                         Â·ÂºÂ¹Ã
&')*+,-.winflags=193844, sortindx=18, maxtasks=0, graph_cpus=0, graph_mems=0
        summclr=1, msgsclr=1, headclr=3, taskclr=1
Job     fieldscur=¥¦¹·º(³´Ã
efghij                            »½@<§Ã
)*+,-./0winflags=193844, sortindx=0, maxtasks=0, graph_cpus=0, graph_mems=0
        summclr=6, msgsclr=6, headclr=7, taskclr=6
Mem     fieldscur=¥º»<½¾¿ÃÃMBNÃD34·Ã
        winflags=193844, sortindx=21, maxtasks=0, graph_cpus=0, graph_mems=0
        summclr=5, msgsclr=5, headclr=4, taskclr=5
Usr     fieldscur=¥¦§¨ª°¹·ºÃ
efghij                               Ã
)+,-./12winflags=193844, sortindx=3, maxtasks=0, graph_cpus=0, graph_mems=0
        summclr=3, msgsclr=3, headclr=2, taskclr=3
Fixed_widest=0, Summ_mscale=0, Task_mscale=0, Zero_suppress=0

I hope the article was useful.