Sometimes it is not comfortable to see meminfo in kilobytes when you have several gigs of RAM. In Linux, it looks like:
And here is how it looks in Mac OS X:
Is there a way to display meminfo in Linux top in terabytes, gigabytes and megabytes?
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When in top, typing capital "E" cycles through different memory units (KiB, MiB, GiB, etc., which are different from kB, MB and GB) in the total memory info:
While lower-case "e" does the same individual process lines:
From the manpage:
2c. MEMORY Usage This portion consists of two lines which may express values in kibibytes (KiB) through exbibytes (EiB) depending on the scaling factor enforced with the 'E' interactive command.
procps-ng version 3.3.9
System: CentOS 7
There is a command-line option which does that:
-M : Detect memory units Show memory units (k/M/G) and display floating point values in the memory summary.
So it is sufficient to run top like that:
-M does not work you can press
E while already in top.
man top (procps-ng version 3.3.9):
E :Extend-Memory-Scale in Summary Area With this command you can cycle through the available summary area memory scaling which ranges from KiB (kibibytes or 1,024 bytes) through EiB (exbibytes or 1,152,921,504,606,846,976 bytes).
If you see a '+' between a displayed number and the following label, it means that top was forced to truncate some portion of that number. By raising the scaling factor, such truncation can be avoided.
top -M doesn't work on any of the Fedora, Debian or Ubuntu distros to my knowledge. I just tried it and it's not in the
procps-ng package that provides
top. There are many implementations of
top so one needs to pay special attention to which they use.
In general it's best to use
free with switching to get the amount of memory free on Linux.
You might have noticed that on CentOS 5 & 6 as well as RHEL 5 & 6 that
top -M appears to work. This is because those distros ship with the original version of
procps. The project was forked and there is now another project
Some of the details as to why there was a fork, from the Fedora Project's page.
Old (legacy) procps tools had no updates for several years and that led to a massive code split caused by a local-only application of distribution specific patches, which were not merged upstream. The project became hardly maintainable since some of the newly written patches were incompatible with sources maintained by other distributors. A similar incompatibility could be noticed in the applications behavior and their command line switches. This inevitable update can be understood as an effort to unify the procps tools across all Linux distributions.
So to be clear, the forked project,
procps-ng is what Debian, Fedora, Ubuntu, and other distros are using, the legacy project, which does support
top -M is still in use of several of the longer term releases that don't keep up with the latest and greatest.
NOTE: I downloaded the latest version of
procps-ng, "procps-ng version 188.8.131.52-14ef" and it too was lacking the
$ ./top/top -version procps-ng version 184.108.40.206-14ef Usage: lt-top -hv | -bcHiOSs -d secs -n max -u|U user -p pid(s) -o field -w [cols]
free with switches, you can see the most likely reason as to why the lack of units feature is missing from
procps-ng's implementation of
$ free -m total used free shared buffers cached Mem: 7782 6506 1276 0 504 1726 -/+ buffers/cache: 4274 3507 Swap: 7823 1429 6394 [saml@greeneggs ~]$ free -k total used free shared buffers cached Mem: 7969492 6663180 1306312 0 516948 1764780 -/+ buffers/cache: 4381452 3588040 Swap: 8011772 1463456 6548316
Rounding becomes problematic, so I believe,
procps's implementation avoids the issue by not offering the ability.
Does an OK job of showing aggregate memory usage.
In my opinion a better tool for looking at memory.
Another useful tool is
nmon for looking at system performance.
So the quick answer : depending on your linux distro, try either :
OR, after starting top, type capital E (then W to write the config).
One of those should work for nearly everybody (except Solaris, of course, where you'd be lucky to have top at all).
bonus tip : every time you start a top instance on a new install, type ExyzW to save colours and highlighting and units - what a relief!
You can use the command line option
E to specify the memory scaling, for example in gigabytes:
$ top -E g
From the top help:
-E :Extend-Memory-Scaling as: -E k | m | g | t | p | e Instructs top to force summary area memory to be scaled as: k - kibibytes m - mebibytes g - gibibytes t - tebibytes p - pebibytes e - exbibytes Later this can be changed with the `E' command toggle.
OS: Ubuntu 20.04