I noticed there is a difference between outputs of free command:On debian:$ free -h             total       used       free     shared    buffers     cachedMem:          4.0G       3.4G       629M         0B        96K       1.3G-/+ buffers/cache:       2.1G       2.0GSwap:         4.0G       1.1G       2.9GOn gentoo:$ free -h              total        used        free      shared  buff/cache   availableMem:            15G        3.7G        9.6G        485M        2.2G         11GSwap:          8.8G        2.6G        6.2GRedhat (at least 7.x) seems to have same output as gentoo. Why is that? Is it possible to display debian style output on gentoo / redhat systems as well? Are both distros using different gnu coreutils?
free command output: gentoo (redhat?) vs debian
linux;command line;memory;utilities
free is provided by procps-ng; Debian 8 has version 3.3.9, which uses the old style with a separate line for buffers/cache, while Gentoo and presumably RHEL 7.x have version 3.3.10 or later which uses the new style. You can see the reasoning behind the change in the corresponding commit message.If you really want the old-style output you can run an older version of procps, but you'll find that distributions will migrate to the newer style by default. The newer style also gives the amount of available memory which is a really useful piece of information (see How can I get the amount of available memory portably across distributions? for details).Somewhat confusingly, version 3.3.9 refers to the format without the buffers/cache line as old format, and you can see it in that version with free -o. So all told:versions 3.3.9 and earlier show by default             total       used       free     shared    buffers     cachedMem:           31G        30G       539M       1.1G       2.2G        15G-/+ buffers/cache:        13G        18GSwap:          31G       180M        31Gversions 3.3.9 and earlier, with -o, show             total       used       free     shared    buffers     cachedMem:           31G        30G       549M       1.1G       2.2G        15GSwap:          31G       180M        31Gversions 3.3.10 and later only show              total        used        free      shared  buff/cache   availableMem:            31G        7.8G        525M        1.1G         23G         22GSwap:           31G        180M         31Gversions 3.3.10 and later also have a wide output mode, -w, which shows              total        used        free      shared     buffers       cache   availableMem:            31G        7.8G        531M        1.1G        2.2G         20G         22GSwap:           31G        180M         31G(This is all on the same system; note how the accounting is more accurate with the later versions.)