Get the machine’s IP address with Nu’s sys net
Nushell’s sys command exposes system info as structured data, so you can query
it with filter syntax instead of scraping text out of ip addr or ifconfig
with awk/grep.
sys net | where name == "wlan0" | get ip.0 | where protocol == "ipv4"Stage by stage
| Stage | What it does |
|---|---|
sys net |
Dumps network interfaces as a table with columns name, mac, ip, sent, recv |
where name == "wlan0" |
Keeps only the row for the wireless interface |
get ip.0 |
Pulls the ip column and descends one level into the nested address table |
where protocol == "ipv4" |
Keeps only the IPv4 address entry |
Append | get address to get the bare IP string:
sys net | where name == "wlan0" | get ip.0 | where protocol == "ipv4" | get address
# 192.168.1.9The output shape
Each row of the inner ip table has four columns:
address— the IP stringprotocol—ipv4,ipv6, oripv46for dual-stack addressesloop— whether this is the loopback addressmulticast— whether multicast is enabled on the address
The gotcha: why .0 matters
The ip column is nested one level deeper than it looks. sys net gives you a
list containing the address table, not the table itself:
ip = [ [ ...address records... ] ] # a list wrapping one tableSo the naive version silently returns 0 rows:
sys net | where name == "wlan0" | get ip | where protocol == "ipv4" # empty!The .0 in get ip.0 descends into the inner table before the filter runs.
Without it the command fails with no error at all — the worst kind of failure,
because nothing tells you the filter just matched nothing.
Related
- nushell-splat-docker-stop — another nushell pipeline trick, same filter syntax