How to retrieve specific cpu, memory and interface statistics only

There is requirement to collect only specific stats like %idle, memfree, available, pmemused etc. I further have to convert the output to a json string and consume it. Is there any UNIX tool which can do the same? I tried sar and sadf in combination, but I am getting a complex json format which I don't require. /usr/bin/sar -r 1 1 -o tmp1 &> 1; /usr/bin/sadf tmp1 -j --iface=eth1 -- -u -r -n DEV I get this output: { "sysstat": { "hosts": [{ "nodename": "ESDNAS1", "sysname": "Linux", "release": "4.4.143-94.47-default", "machine": "x86_64", "number-of-cpus": 8, "file-date": "2019-08-02", "file-utc-time": "04:53:09", "statistics": [{ "timestamp": { "date": "2019-08-02", "time": "04:53:10", "utc": 1, "interval": 1 }, "cpu-load": [{ "cpu": "all", "user": 0.25, "nice": 0.00, "system": 1.00, "iowait": 0.00, "steal": 0.00, "idle": 98.75 }], "memory": { "memfree": 3707764, "avail": 12451860, "memused": 12013448, "memused-percent": 45.01, "buffers": 225176, "cached": 4361204, "commit": 28665304, "commit-percent": 107.41, "active": 13473076, "inactive": 1535816, "dirty": 616 }, "network": { "net-dev": [{ "iface": "eth1", "rxpck": 1.00, "txpck": 1.00, "rxkB": 0.11, "txkB": 0.00, "rxcmp": 0.00, "txcmp": 0.00, "rxmcst": 0.00, "ifutil-percent": 0.00 }] } }], "restarts": [] }] } } I am looking for something like this (or close one which is simple): { "sysstat": { "hosts": [ { "nodename": "HOSTNAME", "statistics": [ { "timestamp": { "date": "2019-08-02", "time": "04:53:10" }, "cpu-load": [ { "idle": 98.75 } ], "memory": { "memfree": 3707764, "avail": 12451860, "memused-percent": 45.01 }, "network": { "net-dev": [ { "iface": "eth1", "rxpck": 1, "txpck": 1, "ifutil-percent": 0 } ] } } ], "restarts": [] } ] } }