Remove slash character in JSON response using jq - jq

Question

Docker Engine API returns container name with / appended
{
"Id": "8dfafdbc3a40",
"Names": [
"/boring_feynman"
],
"Image": "ubuntu:latest",
"ImageID": "d74508fb6632491cea586a1fd7d748dfc5274cd6fdfedee309ecdcbc2bf5cb82",
"Command": "echo 1",
"Created": 1367854155,
"State": "Exited",
"Status": "Exit 0",
"Ports": [{
"PrivatePort": 2222,
"PublicPort": 3333,
"Type": "tcp"
}],
"Labels": {
"com.example.vendor": "Acme",
"com.example.license": "GPL",
"com.example.version": "1.0"
},
"SizeRw": 12288,
"SizeRootFs": 0,
"HostConfig": {
"NetworkMode": "default"
},
"NetworkSettings": {
"Networks": {}
},
"Mounts": [{
"Name": "fac362...80535",
"Source": "/data",
"Destination": "/data",
"Driver": "local",
"Mode": "ro,Z",
"RW": false,
"Propagation": ""
}]
}
I want to remove the slash so the response can be used as a table in JQ:
jq -r '(["Names","Image"] | (., map(length*"-"))), (.[] | [.Names, .Image]) | #tsv'
Currently, when I run the above, I get:
jq: error (at <stdin>:1): array (["/boring_feynman"]) is not valid in a csv row

Answer 1

The problem is not because of / in the .Names field, but in your expression. For filters like #csv or #tsv to work, the values need to be in a scalar format and in an array. But your expression .Name in of type array.
So basically you are passing this result to the #tsv function
[
[
"/boring_feynman"
],
"ubuntu:latest"
]
instead of
[
"/boring_feynman",
"ubuntu:latest"
]
So modifying your filter, you can do below for the JSON in question.
jq -r '(["Names","Image"] | (., map(length*"-"))), ([.Names[], .Image]) | #tsv'
or if you still want to remove the /, use gsub() function
jq -r '(["Names","Image"] | (., map(length*"-"))), ([ (.Names[] | gsub("^/";"")), .Image]) | #tsv'