How can I only get the boolean value from the return of sysctl, MacOS-CodePudding

I am trying to get the return Boolean value of the command: sysctl debug.lowpri_throttle_enabled, in a shell script (run with zsh).

This command is for knowing whether macOS enables the limit of speed of low-order tasks (i.e. time machine).

Here is the script I have done now:

value=$(sysctl debug.lowpri_throttle_enabled)
echo $value

The output I got is:

>>>debug.lowpri_throttle_enabled: 0

But I just want 0/1 as output, how can I just get the boolean value but not the whole string? Thanks.

CodePudding user response：

I have found the solution. Reference : https://ss64.com/osx/sysctl.html

With adding -n as option, it will only return the value.

e.g.

>>>sysctl -n debug.lowpri_throttle_enabled
0
>>>sudo sysctl debug.lowpri_throttle_enabled=1
>>>sysctl -n debug.lowpri_throttle_enabled
1

According to the description, -n is for:

Show only variable values, not their names. This option is useful for setting shell variables.

And -b is for:

Force the value of the variable(s) to be output in raw, binary format. No names are printed and no terminating newlines are output.

But I don't know why only -n works in this case, -b doesn't.