Identifying Mac laptops and desktops from the command line by checking for a built-in battery

Every so often, it may be necessary for Mac admins to deploy a script that can apply different settings to Mac desktops and laptops. A good example may be using the pmset command to apply Energy Saver settings, where you may want to apply one set of power management settings to laptops and a different set to desktops.

	#!/bin/bash
	# Set separate power management settings for desktops and laptops
	# If it's a laptop, the power management settings for "Battery" are set to have the computer sleep in 15 minutes,
	# disk will spin down in 10 minutes, the display will sleep in 5 minutes and the display itself will dim to
	# half-brightness before sleeping. While plugged into the AC adapter, the power management settings for "Charger"
	# are set to have the computer never sleep, the disk doesn't spin down, the display sleeps after 30 minutes and
	# the display dims before sleeping.
	#
	# If it's not a laptop (i.e. a desktop), the power management settings are set to have the computer never sleep,
	# the disk doesn't spin down, the display sleeps after 30 minutes and the display dims before sleeping.
	#
	# Detects if this Mac is a laptop or not by checking the model ID for the word "Book" in the name.
	IS_LAPTOP=$(/usr/sbin/system_profiler SPHardwareDataType | grep "Model Identifier" | grep "Book")
	if [[ -n "$IS_LAPTOP" ]]; then
	/usr/bin/pmset -b sleep 15 disksleep 10 displaysleep 5 halfdim 1
	/usr/bin/pmset -c sleep 0 disksleep 0 displaysleep 30 halfdim 1
	else
	/usr/bin/pmset sleep 0 disksleep 0 displaysleep 30 halfdim 1
	fi

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powersetings.sh

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In the example above, the Model Identifier information from the system_profiler command is used to help identify if the Mac is a desktop or laptop. In this case, the Model Identifier information is checked to see if the model identifier contains “Book”.

If it does, it’s a laptop. Otherwise, it’s a desktop:

/usr/sbin/system_profiler SPHardwareDataType | grep "Model Identifier" | grep "Book"

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gistfile1.txt

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However, the latest Mac laptops’ model identifier does not contain “Book”. This means that this identification method should no longer be considered reliable.

What’s an alternative way to check? One way is to use the ioreg command to see if the Mac in question has a built-in battery or not. Laptops will have a built-in battery and desktops will not. For more details, please see below the jump.

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Update – 12-29-2022: It appears my original choice of detection criteria of using built-in with the ioreg command was not universally returning no output data for desktops, as I hadn’t tested against Apple Silicon Mac desktops. Apple Silicon Mac desktops share a number of characteristics with Apple Silicon laptops, including having the following command respond with the following output:

Yes

	username@computername ~ % /usr/sbin/ioreg -c AppleSmartBattery -r | awk '/built-in/ {print $3}'
	Yes
	username@computername ~ %

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gistfile1.txt

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However, there is another criteria we can search for which should provide better results, which is to use BatteryInstalled in place of built-in as criteria when running the ioreg command:

/usr/sbin/ioreg -c AppleSmartBattery -r | awk '/BatteryInstalled/ {print $3}'

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gistfile1.txt

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On a laptop, the following output should be returned:

Yes

	username@computername ~ % /usr/sbin/ioreg -c AppleSmartBattery -r | awk '/BatteryInstalled/ {print $3}'
	Yes
	username@computername ~ %

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gistfile1.txt

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On a desktop, either the following output or no output should be returned:

No

	username@computername ~ % /usr/sbin/ioreg -c AppleSmartBattery -r | awk '/BatteryInstalled/ {print $3}'
	No
	username@computername ~ %

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gistfile1.txt

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No output:

	username@computername ~ % /usr/sbin/ioreg -c AppleSmartBattery -r | awk '/BatteryInstalled/ {print $3}'
	username@computername ~ %

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gistfile1.txt

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I’ve updated this blog post to now reference the BatteryInstalled criteria in place of the built-in criteria previously referenced.

Note: There is an edge case where it’s possible a laptop may have its built-in battery removed and thus respond with No or return no output, like a desktop would. Mac laptops made since 2009 and later have non-removable batteries built into the laptop, so this scenario shouldn’t be a common one for most environments, but it’s worth mentioning if you have a non-zero number of Mac laptops with their built-in batteries removed.

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You can use the ioreg command shown below to query the information for the AppleSmartBattery hardware driver (currently used by macOS for its battery management) and check whether the Mac has a built-in battery or not:

/usr/sbin/ioreg -c AppleSmartBattery -r | awk '/BatteryInstalled/ {print $3}'

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gistfile1.txt

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On a laptop, the following command should return Yes:

	username@computername ~ % /usr/sbin/ioreg -c AppleSmartBattery -r | awk '/BatteryInstalled/ {print $3}'
	Yes
	username@computername ~ %

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gistfile1.txt

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On a desktop, the same command should return No or no output:

No

	username@computername ~ % /usr/sbin/ioreg -c AppleSmartBattery -r | awk '/BatteryInstalled/ {print $3}'
	No
	username@computername ~ %

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gistfile1.txt

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No output:

	username@computername ~ % /usr/sbin/ioreg -c AppleSmartBattery -r | awk '/BatteryInstalled/ {print $3}'
	username@computername ~ %

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gistfile1.txt

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You should be able to use this command to update the example script for setting power management to correctly identify laptops vs. desktops again:

	#!/bin/bash
	# Set separate power management settings for desktops and laptops
	# If it's a laptop, the power management settings for "Battery" are set to have the computer sleep in 15 minutes,
	# disk will spin down in 10 minutes, the display will sleep in 5 minutes and the display itself will dim to
	# half-brightness before sleeping. While plugged into the AC adapter, the power management settings for "Charger"
	# are set to have the computer never sleep, the disk doesn't spin down, the display sleeps after 30 minutes and
	# the display dims before sleeping.
	#
	# If it's not a laptop (i.e. a desktop), the power management settings are set to have the computer never sleep,
	# the disk doesn't spin down, the display sleeps after 30 minutes and the display dims before sleeping.
	#
	# Detects if this Mac is a laptop or not by checking for a built-in battery.
	IS_LAPTOP=$(/usr/sbin/ioreg -c AppleSmartBattery -r | awk '/BatteryInstalled/ {print $3}')
	if [[ "$IS_LAPTOP" = "Yes" ]]; then
	/usr/bin/pmset -b sleep 15 disksleep 10 displaysleep 5 halfdim 1
	/usr/bin/pmset -c sleep 0 disksleep 0 displaysleep 30 halfdim 1
	else
	/usr/bin/pmset sleep 0 disksleep 0 displaysleep 30 halfdim 1
	fi

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powersettings.sh

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Note: The AppleSmartBattery hardware driver is being queried by the ioreg command to gather this information. If Apple ever changes the name or the functionality of the AppleSmartBattery hardware driver, this method may stop working and need to be updated for the new name or functionality.