{
    "mode": "man",
    "parameter": "FREE",
    "section": "",
    "url": "https://www.chedong.com/phpMan.php/man/FREE/json",
    "generated": "2026-10-22T13:09:21Z",
    "synopsis": "free [options]",
    "sections": {
        "NAME": {
            "content": "free - Display amount of free and used memory in the system\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "free [options]\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "free  displays  the  total amount of free and used physical and swap memory in the system, as\nwell as the buffers and caches used by the kernel. The information  is  gathered  by  parsing\n/proc/meminfo. The displayed columns are:\n\ntotal  Total usable memory (MemTotal and SwapTotal in /proc/meminfo). This includes the phys‐\nical and swap memory minus a few reserved bits and kernel binary code.\n\nused   Used or unavailable memory (calculated as total - available)\n\nfree   Unused memory (MemFree and SwapFree in /proc/meminfo)\n\nshared Memory used (mostly) by tmpfs (Shmem in /proc/meminfo)\n",
            "subsections": [
                {
                    "name": "buffers",
                    "content": "Memory used by kernel buffers (Buffers in /proc/meminfo)\n\ncache  Memory used by the page cache and slabs (Cached and SReclaimable in /proc/meminfo)\n"
                },
                {
                    "name": "buff/cache",
                    "content": "Sum of buffers and cache\n"
                },
                {
                    "name": "available",
                    "content": "Estimation  of  how  much  memory  is available for starting new applications, without\nswapping. Unlike the data provided by the cache or free fields, this field takes  into\naccount  page  cache  and also that not all reclaimable memory slabs will be reclaimed\ndue to items being in use (MemAvailable in /proc/meminfo, available on  kernels  3.14,\nemulated on kernels 2.6.27+, otherwise the same as free)\n"
                }
            ]
        },
        "OPTIONS": {
            "content": "",
            "subsections": [
                {
                    "name": "-b --bytes",
                    "content": "Display the amount of memory in bytes.\n",
                    "flag": "-b",
                    "long": "--bytes"
                },
                {
                    "name": "-k --kibi",
                    "content": "Display the amount of memory in kibibytes.  This is the default.\n",
                    "flag": "-k",
                    "long": "--kibi"
                },
                {
                    "name": "-m --mebi",
                    "content": "Display the amount of memory in mebibytes.\n",
                    "flag": "-m",
                    "long": "--mebi"
                },
                {
                    "name": "-g --gibi",
                    "content": "Display the amount of memory in gibibytes.\n\n--tebi Display the amount of memory in tebibytes.\n\n--pebi Display the amount of memory in pebibytes.\n\n--kilo Display the amount of memory in kilobytes. Implies --si.\n\n--mega Display the amount of memory in megabytes. Implies --si.\n\n--giga Display the amount of memory in gigabytes. Implies --si.\n\n--tera Display the amount of memory in terabytes. Implies --si.\n\n--peta Display the amount of memory in petabytes. Implies --si.\n",
                    "flag": "-g",
                    "long": "--gibi"
                },
                {
                    "name": "-h --human",
                    "content": "Show  all  output fields automatically scaled to shortest three digit unit and display\nthe units of print out.  Following units are used.\n\nB = bytes\nKi = kibibyte\nMi = mebibyte\nGi = gibibyte\nTi = tebibyte\nPi = pebibyte\n\nIf unit is missing, and you have exbibyte of RAM or swap, the number is  in  tebibytes\nand columns might not be aligned with header.\n",
                    "flag": "-h",
                    "long": "--human"
                },
                {
                    "name": "-w --wide",
                    "content": "Switch  to  the  wide mode. The wide mode produces lines longer than 80 characters. In\nthis mode buffers and cache are reported in two separate columns.\n",
                    "flag": "-w",
                    "long": "--wide"
                },
                {
                    "name": "-c --count _",
                    "content": "Display the result count times.  Requires the -s option.\n",
                    "flag": "-c",
                    "long": "--count"
                },
                {
                    "name": "-l --lohi",
                    "content": "Show detailed low and high memory statistics.\n",
                    "flag": "-l",
                    "long": "--lohi"
                },
                {
                    "name": "-L --line",
                    "content": "Show output on a single line, often used with the -s option to show memory  statistics\nrepeatedly.\n",
                    "flag": "-L",
                    "long": "--line"
                },
                {
                    "name": "-s --seconds _",
                    "content": "Continuously  display  the  result delay  seconds apart.  You may actually specify any\nfloating point number for delay using either . or , for decimal point.   usleep(3)  is\nused for microsecond resolution delay times.\n\n--si   Use kilo, mega, giga etc (power of 1000) instead of kibi, mebi, gibi (power of 1024).\n",
                    "flag": "-s",
                    "long": "--seconds"
                },
                {
                    "name": "-t --total",
                    "content": "Display a line showing the column totals.\n",
                    "flag": "-t",
                    "long": "--total"
                },
                {
                    "name": "-v --committed",
                    "content": "Display  a  line  showing  the memory commit limit and amount of committed/uncommitted\nmemory. The total column on this line will display the  memory  commit  limit.    This\nline is relevant if memory overcommit is disabled.\n\n--help Print help.\n",
                    "flag": "-v",
                    "long": "--committed"
                },
                {
                    "name": "-V --version",
                    "content": "Display version information.\n",
                    "flag": "-V",
                    "long": "--version"
                }
            ]
        },
        "FILES": {
            "content": "/proc/meminfo\nmemory information\n",
            "subsections": []
        },
        "BUGS": {
            "content": "The  value for the shared column is not available from kernels before 2.6.32 and is displayed\nas zero.\n\nPlease send bug reports to\nprocps@freelists.org\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "ps(1), slabtop(1), top(1), vmstat(8).\n\nprocps-ng                                    2023-05-02                                      FREE(1)",
            "subsections": []
        }
    },
    "summary": "free - Display amount of free and used memory in the system",
    "flags": [
        {
            "flag": "-b",
            "long": "--bytes",
            "arg": null,
            "description": "Display the amount of memory in bytes."
        },
        {
            "flag": "-k",
            "long": "--kibi",
            "arg": null,
            "description": "Display the amount of memory in kibibytes. This is the default."
        },
        {
            "flag": "-m",
            "long": "--mebi",
            "arg": null,
            "description": "Display the amount of memory in mebibytes."
        },
        {
            "flag": "-g",
            "long": "--gibi",
            "arg": null,
            "description": "Display the amount of memory in gibibytes. --tebi Display the amount of memory in tebibytes. --pebi Display the amount of memory in pebibytes. --kilo Display the amount of memory in kilobytes. Implies --si. --mega Display the amount of memory in megabytes. Implies --si. --giga Display the amount of memory in gigabytes. Implies --si. --tera Display the amount of memory in terabytes. Implies --si. --peta Display the amount of memory in petabytes. Implies --si."
        },
        {
            "flag": "-h",
            "long": "--human",
            "arg": null,
            "description": "Show all output fields automatically scaled to shortest three digit unit and display the units of print out. Following units are used. B = bytes Ki = kibibyte Mi = mebibyte Gi = gibibyte Ti = tebibyte Pi = pebibyte If unit is missing, and you have exbibyte of RAM or swap, the number is in tebibytes and columns might not be aligned with header."
        },
        {
            "flag": "-w",
            "long": "--wide",
            "arg": null,
            "description": "Switch to the wide mode. The wide mode produces lines longer than 80 characters. In this mode buffers and cache are reported in two separate columns."
        },
        {
            "flag": "-c",
            "long": "--count",
            "arg": null,
            "description": "Display the result count times. Requires the -s option."
        },
        {
            "flag": "-l",
            "long": "--lohi",
            "arg": null,
            "description": "Show detailed low and high memory statistics."
        },
        {
            "flag": "-L",
            "long": "--line",
            "arg": null,
            "description": "Show output on a single line, often used with the -s option to show memory statistics repeatedly."
        },
        {
            "flag": "-s",
            "long": "--seconds",
            "arg": null,
            "description": "Continuously display the result delay seconds apart. You may actually specify any floating point number for delay using either . or , for decimal point. usleep(3) is used for microsecond resolution delay times. --si Use kilo, mega, giga etc (power of 1000) instead of kibi, mebi, gibi (power of 1024)."
        },
        {
            "flag": "-t",
            "long": "--total",
            "arg": null,
            "description": "Display a line showing the column totals."
        },
        {
            "flag": "-v",
            "long": "--committed",
            "arg": null,
            "description": "Display a line showing the memory commit limit and amount of committed/uncommitted memory. The total column on this line will display the memory commit limit. This line is relevant if memory overcommit is disabled. --help Print help."
        },
        {
            "flag": "-V",
            "long": "--version",
            "arg": null,
            "description": "Display version information."
        }
    ],
    "examples": [],
    "see_also": [
        {
            "name": "ps",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/ps/1/json"
        },
        {
            "name": "slabtop",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/slabtop/1/json"
        },
        {
            "name": "top",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/top/1/json"
        },
        {
            "name": "vmstat",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/vmstat/8/json"
        }
    ],
    "tldr": {
        "source": "official",
        "description": "Display amount of free and used memory in the system.",
        "examples": [
            {
                "description": "Display system memory",
                "command": "free"
            },
            {
                "description": "Display memory in Bytes/KB/MB/GB",
                "command": "free -{{b|k|m|g}}"
            },
            {
                "description": "Display memory in human-readable units",
                "command": "free {{-h|--human}}"
            },
            {
                "description": "Refresh the output every 2 seconds",
                "command": "free {{-s|--seconds}} 2"
            }
        ]
    }
}