Converting JSON pretty print to one line

问题:

I have a command that I run and it gives an output like below:

{
"endpointApplications": {
    "App_Name": {
        "connectionState": "Disconnected",
        "connectionTime": "No connection was established",
        "linkAttributes": {
            "ackSettings": {
                "dataAckEnabled": "true",
                "dataAckTimeout": "5000",
                "dataNakRetryLimit": "0",
                "retransmitDelay": "500"
            },
            "keepAliveSettings": {
                "keepAliveAckTimeout": "5000",
                "keepAliveInterval": "30000"
            },
            "logTraffic": "false",
            "port": "9999",
            "role": "server"
        },
        "protocol": "snmp"
    }
},
"queueStats": {}
}

I would need the output to be in one line like below:

{"endpointApplications": {"app_name": {"connectionState": "Disconnected","connectionTime": "No connection was established","linkAttributes": {"ackSettings":{"dataAckEnabled": "true","dataAckTimeout": "5000","dataNakRetryLimit": "0","retransmitDelay": "500"},"keepAliveSettings":{"keepAliveAckTimeout": "5000","keepAliveInterval": "30000"},"logTraffic": "false","port": "9999","role": "server"},"protocol": "snmp"}},"queueStats":{}}

I tried using awk and sed combining different parameters but I can't get to work without losing the JSON format.

回答1:

jq or any other json aware tool is best suited for json file manipulation.However here is awk based solution.

awk -v RS= '{$1=$1}1' input.json
{ "endpointApplications": { "App_Name": { "connectionState": "Disconnected", "connectionTime": "No connection was established", "linkAttributes": { "ackSettings": { "dataAckEnabled": "true", "dataAckTimeout": "5000", "dataNakRetryLimit": "0", "retransmitDelay": "500" }, "keepAliveSettings": { "keepAliveAckTimeout": "5000", "keepAliveInterval": "30000" }, "logTraffic": "false", "port": "9999", "role": "server" }, "protocol": "snmp" } }, "queueStats": {} }

Note: This solution is mainly for the legacy systems not having tools like jq and have no chance to get them installed due to some reasons.

回答2:

You should use jq for stuff like that:

jq -c . input.txt

An alternative quick a dirty solution would be to use sed & tr:

sed -e 's/^ *//' < input.txt | tr -d '\n'

although I would recommend using jq which is designed for manipulating JSON. jq is like sed for JSON. Manipulating JSON textually with sed/awk/etc is not guaranteed to produce semantically equivalent JSON.