Remote ash-command from my ubuntu box

Installing and Using OpenWrt
1

I would like to find out

brand
model
openwrt-version

of a given ip-address of an openwrt-device using my linux box.

Actually my pc uses bash, but openwrt ash.

The pc can connect to the openwrt-device with keys and without a password.

I can query this when I connect to the openwrt device via ssh, but I want to do this using a script in my ubuntu-box.

2

the shell is not important, characteristic openwrt sysinfo is like this
ssh root@openwrt.lan ubus call system board

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3 
$ ssh root@192.168.178.22 ubus call system board | grep hostname | cut -f4 -d"\""
WSM20-K1

That's fine, but how can I do it this way:

var=$(ssh root@192.168.178.22 ubus call system board)

and then

$ echo $var
{ "kernel": "6.6.86", "hostname": "WSM20-K1", "system": "MediaTek MT7621 ver:1 eco:3", "model": "Zyxel WSM20", "board_name": "zyxel,wsm20", "rootfs_type": "squashfs", "release": { "distribution": "OpenWrt", "version": "24.10.1", "revision": "r28597-0425664679", "target": "ramips/mt7621", "description": "OpenWrt 24.10.1 r28597-0425664679", "builddate": "1744562312" } }

Obviously it is not possible to select a line with grep.

4

ubus call system board output is in JSON format, so you will need to use a tool like jq to extract the data you need. For example: echo $var | jq .hostname

6 Likes
5

For comparison:

ssh root@192.168.178.22 ubus call system board
{
	"kernel": "6.6.86",
	"hostname": "WSM20-K1",
	"system": "MediaTek MT7621 ver:1 eco:3",
	"model": "Zyxel WSM20",
	"board_name": "zyxel,wsm20",
	"rootfs_type": "squashfs",
	"release": {
		"distribution": "OpenWrt",
		"version": "24.10.1",
		"revision": "r28597-0425664679",
		"target": "ramips/mt7621",
		"description": "OpenWrt 24.10.1 r28597-0425664679",
		"builddate": "1744562312"
	}
}

For script:

var=$(ssh root@192.168.178.22 ubus call system board)

openwrt_hostname=$(echo $var | jq .hostname | cut -f2 -d"\"" | tr '[:upper:]' '[:lower:]')

openwrt_version=$(echo $var | jq .release | grep version | cut -f4 -d"\"" |sed -e 's/\./-/g')

uniq_openwrt_dir="$openwrt_hostname""_""$openwrt_version"

$ echo $uniq_openwrt_dir
wsm20-k1_24-10-1

goal is to create a unique directory name for every openwrt device, where the configuration is synced with rsync.

The above code works, but maybe this can be done better.

The ip_address will be a variable in the script.

6

Most of the time you don't need other tools like grep|cut|sed:

$ echo $var | jq -r .release.version
24.10.1
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