TIL: GNU `time` can show memory usage

We are all used to running time foo to get coarse numbers on some executable's runtime. But turns out GNU time util can measure much more. Here's the output for \time -v ls:

Command being timed: "ls"
User time (seconds): 0.00
System time (seconds): 0.00
Percent of CPU this job got: 100%
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.00
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 2176
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 0
Minor (reclaiming a frame) page faults: 111
Voluntary context switches: 1
Involuntary context switches: 0
Swaps: 0
File system inputs: 0
File system outputs: 0
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 0

RSS (memory usage), page fault count, context switches, signals — there's so much to dig into!

Secondary TIL: time is actually a shell builtin! So you'll probably have to install GNU time if it isn't already present in your machine, and then use \time to invoke it.

Tertiary TIL: We can use \foo to bypass the shell builtin and look up the executable foo directly!