Question

I connect to my rooted phone through adb shell command and I run
the vmstat command so as to watch various system resources. Is
there a way to redirect vmstat’s output to a file. I tried:

vmstat > /sdcard/vmstat_output.txt

but it doesn’t work.. It creates the file but there is no data inside..

Any ideas?

Answer 1

Ok, I fixed the problem. I download the source from here and I added one extra line:

fflush(stdout);

right after the print_line command (line: 134). Then, I cross-compiled the vmstat.c with
agcc:

agcc vmstat.c -o vmstat

and put the file to the /sdcard/ through the adb:

adb push vmstat /sdcard/

Now the redirection works
perfectly, as after every print_line call, the data are flushed to the file. As Mark Polhamus mentioned,
the problem was the fact that vmstat is a block-buffered command, which means that a buffer
has to be filled with data first and then this data will be flushed to the file..

Thank you very much Mark! 🙂