Terminal command to show connected displays/monitors/resolutions? - macos

Question

Is there a way to get the information about connected monitors and displays and their resolutions via the terminal in OS X?
I have some installations that run on multiple monitors and sometimes with a GFLW window that seem to not open if a monitor is not attached - I would like to have a check for whether a monitor is attached properly and maybe dump that to a log file, but I haven't found a programmatic way to do that without getting deep into Obj-C/Cocoa

Answer 1

You can use system_profiler SPDisplaysDataType or defaults read /Library/Preferences/com.apple.windowserver.plist:
$ system_profiler SPDisplaysDataType
Graphics/Displays:
NVIDIA GeForce GT 640M:
Chipset Model: NVIDIA GeForce GT 640M
Type: GPU
Bus: PCIe
PCIe Lane Width: x16
VRAM (Total): 512 MB
Vendor: NVIDIA (0x10de)
Device ID: 0x0fd8
Revision ID: 0x00a2
ROM Revision: 3707
Displays:
iMac:
Display Type: LCD
Resolution: 1920 x 1080
Pixel Depth: 32-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes
Built-In: Yes
Connection Type: DisplayPort
$ defaults read /Library/Preferences/com.apple.windowserver.plist
{
DisplayResolutionEnabled = 1;
DisplaySets = (
(
{
Active = 1;
Depth = 4;
DisplayID = 69731456;
DisplayProductID = 40978;
DisplaySerialNumber = 0;
DisplayVendorID = 1552;
Height = 1080;
IODisplayLocation = "IOService:/AppleACPIPlatformExpert/PCI0#0/AppleACPIPCI/P0P2#1/IOPCI2PCIBridge/GFX0#0/NVDA,Display-A#0/NVDA";
IOFlags = 7;
LimitsHeight = 1080;
LimitsOriginX = 0;
LimitsOriginY = 0;
LimitsWidth = 1920;
MirrorID = 0;
Mirrored = 0;
Mode = {
BitsPerPixel = 32;
BitsPerSample = 8;
DepthFormat = 4;
Height = 1080;
IODisplayModeID = "-2147479552";
IOFlags = 7;
Mode = 1;
PixelEncoding = "--------RRRRRRRRGGGGGGGGBBBBBBBB";
RefreshRate = 0;
SamplesPerPixel = 3;
UsableForDesktopGUI = 1;
Width = 1920;
kCGDisplayBytesPerRow = 7680;
kCGDisplayHorizontalResolution = 103;
kCGDisplayModeIsInterlaced = 0;
kCGDisplayModeIsSafeForHardware = 1;
kCGDisplayModeIsStretched = 0;
kCGDisplayModeIsTelevisionOutput = 0;
kCGDisplayModeIsUnavailable = 0;
kCGDisplayModeSuitableForUI = 1;
kCGDisplayPixelsHigh = 1080;
kCGDisplayPixelsWide = 1920;
kCGDisplayResolution = 1;
kCGDisplayVerticalResolution = 103;
};
OriginX = 0;
OriginY = 0;
PixelEncoding = "--------RRRRRRRRGGGGGGGGBBBBBBBB";
Resolution = 1;
Unit = 0;
UnmirroredHeight = 1080;
UnmirroredLimitsHeight = 1080;
UnmirroredLimitsOriginX = 0;
UnmirroredLimitsOriginY = 0;
UnmirroredLimitsWidth = 1920;
UnmirroredMode = {
BitsPerPixel = 32;
BitsPerSample = 8;
DepthFormat = 4;
Height = 1080;
IODisplayModeID = "-2147479552";
IOFlags = 7;
Mode = 1;
PixelEncoding = "--------RRRRRRRRGGGGGGGGBBBBBBBB";
RefreshRate = 0;
SamplesPerPixel = 3;
UsableForDesktopGUI = 1;
Width = 1920;
kCGDisplayBytesPerRow = 7680;
kCGDisplayHorizontalResolution = 103;
kCGDisplayModeIsInterlaced = 0;
kCGDisplayModeIsSafeForHardware = 1;
kCGDisplayModeIsStretched = 0;
kCGDisplayModeIsTelevisionOutput = 0;
kCGDisplayModeIsUnavailable = 0;
kCGDisplayModeSuitableForUI = 1;
kCGDisplayPixelsHigh = 1080;
kCGDisplayPixelsWide = 1920;
kCGDisplayResolution = 1;
kCGDisplayVerticalResolution = 103;
};
UnmirroredOriginX = 0;
UnmirroredOriginY = 0;
UnmirroredResolution = 1;
UnmirroredWidth = 1920;
Width = 1920;
}
)
);
ForceOldStyleMemoryManagement = 0;
}

Answer 2

You can also use a command-line tool called cscreen:
# install homebrew if you don't have it already
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
# install cscreen
brew install --cask cscreen
# list displays
cscreen -l
output:
DisplayID Index Depth Width Height Refresh
1 1 32 1440 900 60
2 2 32 1920 1080 60
use -h to display all usage options
Note:
The first time you try to open the cscreen the os will not allow it because it isn't signed.
You have to go to Security & Privacy in System Preferences and allow it.
Homebrew package search