When you want to see how strong your Wi-Fi actually is from the Terminal — signal, noise, channel, the negotiated rate — wdutil is the built-in tool that answers it on current macOS. It replaced airport, the private-framework binary older guides still reach for, which no longer ships. The whole tool is one snapshot command plus a handful of subcommands, and reading its output is mostly a matter of knowing which lines matter. Everything below was run on macOS 26.5.2.
sudo wdutil info — the one command and what it prints
wdutil needs sudo, and info is the subcommand you will use nine times out of ten. It prints a full snapshot grouped into sections — NETWORK, WIFI, BLUETOOTH, AWDL, POWER, and three short counters headed WIFI FAULTS LAST HOUR, WIFI RECOVERIES LAST HOUR, and WIFI LINK TESTS LAST HOUR. The NETWORK block ends with an Apple : Reachable line, a built-in connectivity check, and the fault counters are worth a glance when a connection has been dropping — a non-empty count is macOS telling you the link reset itself recently. The section that matters for signal is WIFI:
$ sudo wdutil info
[ ... NETWORK, then: ]
WIFI
MAC Address : <redacted>
Interface Name : en0
Power : On [On]
Op Mode : STA
SSID : <redacted>
BSSID : <redacted>
RSSI : -32 dBm
CCA : 15 %
Noise : -92 dBm
Tx Rate : 1200.0 Mbps
Security : WPA3 Personal
PHY Mode : 11ax
MCS Index : 11
NSS : 2
Channel : 5g44/80
# MAC/SSID/BSSID are redacted by wdutil itself; the other lines are untouched. Trimmed to the WIFI section.Op Mode : STA means the interface is a normal station (a client joined to an access point), and Power : On confirms the radio is up. Everything else on that list is what the old airport -I used to report, and then some.
Reading the signal — RSSI, Noise, and SNR
RSSI is the received signal strength in dBm. It is a negative number, and closer to zero is stronger. As a rough field guide, roughly -30 to -50 dBm is what you see sitting near the access point, around -60 is comfortable, about -70 is the practical floor for smooth video and calls, and -80 or lower is where drops and slow rates start. The -32 dBm above is a laptop a few feet from the router.
Noise is the background noise floor, also in dBm, where more negative is better; -92 dBm is quiet. What actually decides whether a link is clean is the gap between the two — the signal-to-noise ratio. Subtract noise from signal: -32 minus -92 is 60 dB of headroom, which is excellent. As a guide, an SNR above about 40 dB is great, around 25 dB is fine, and under 15 dB is where throughput falls apart even if the raw RSSI still looks acceptable. CCA (clear channel assessment, shown as a percentage) is roughly how busy the channel is; a high figure means a lot of competing traffic on the air, which no amount of signal strength fixes.
Channel, PHY mode, rate, and security
Channel : 5g44/80 packs three facts into one token: the band (5 GHz), the channel number (44), and the channel width (80 MHz). A wider channel carries more throughput but overlaps more neighbors, so on a crowded 2.4 GHz band a narrower width is often steadier. PHY Mode : 11ax is the 802.11 generation in use — 11ax is Wi-Fi 6, 11ac is Wi-Fi 5 — and it caps what rates are even possible. Tx Rate is the currently negotiated transmit rate in Mbps, which rises and falls with signal quality; it is a link rate, not your internet speed. MCS Index and NSS describe how that rate is built: the modulation-and-coding step and the number of spatial streams (NSS : 2 means two streams). Security : WPA3 Personal is the encryption the network negotiated, which is the fastest way to confirm from the Terminal that you actually landed on WPA3 rather than a weaker mode.
What wdutil does not do (it isn’t a scanner)
Autocomplete suggests things like “wdutil list wifi networks” and “wdutil monitor mode,” and neither exists. wdutil reports on the link you are already on; it does not scan the air for nearby networks and has no monitor mode. Its actual subcommand set is short:
$ wdutil
usage: sudo wdutil diagnose [-q] [-f outputDirectoryPath]
sudo wdutil info
sudo wdutil log [{+|-} {system|wifi}]+
sudo wdutil dump
sudo wdutil clean
sudo wdutil privateMAC={0/1}The old airport -s scan left with the rest of airport, so there is no drop-in Terminal replacement for listing surrounding networks. That job now lives in the graphical Wireless Diagnostics app (hold Option, click the Wi-Fi menu, open Wireless Diagnostics, then use its Scan window) or a third-party scanner.
The other subcommands
Beyond info, the one most people reach for is diagnose. sudo wdutil diagnose -f ~/Desktop collects a full Wi-Fi diagnostics bundle into a folder — the command-line equivalent of the report the graphical Wireless Diagnostics produces — and by default shows a legal prompt and opens the result in Finder, which -q suppresses. sudo wdutil log + wifi turns on verbose Wi-Fi logging (and - turns it back off), useful when you are trying to capture an intermittent problem. sudo wdutil privateMAC=0 or =1 toggles the private, randomized Wi-Fi MAC address for the current network straight from the command line, the same switch buried in the network’s settings. dump and clean handle lower-level state and cleanup and are rarely needed day to day.
wdutil and the airport command it replaced
For years the answer to “show the Wi-Fi signal from the Terminal” was airport -I, a binary tucked inside a private framework. It is gone on macOS 26.5.2:
$ ls /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport
No such file or directory
$ which airport
airport not foundApple deprecated it years ago and has now removed the file, so any tutorial still leading with airport -I or airport -s is teaching a command that no longer runs. The WIFI block from wdutil info covers the same signal, channel, and rate fields airport -I printed, so it is a direct replacement for reading link state — just not for scanning.
Redact the output before you share it
One thing to know before pasting a wdutil info dump into a forum post: it is only partly self-redacting. On 26.5.2 it replaces MAC Address, SSID, and BSSID with <redacted> on its own, but it still prints your IPv4/IPv6 addresses and DNS servers in clear, and the BLUETOOTH section lists every paired device by name and address. Trim to the WIFI section and scrub the addresses by hand before you share it. This tool is one stop in a wider set — for the full walk from “is the link up” through DNS and routing, see the Mac network diagnostics cheat sheet.