Sum bytes read by a process (and children)

count_read_io.sh

#!/bin/bash -e
# Measure the bytes read by a command
# count_command_io <cmd> <args>*
# Credit to shodanex from https://stackoverflow.com/a/8853287

if [ -z $@ ] ; then
        echo "Usage: $0 <cmd> <args>*"
        exit 1
fi

# Create a fifo in a temp directory
logdir=$(mktemp -d)
logpipe="$logdir/logpipe"
# The fifo saves us from consuming a lot of disk space for the strace log
mkfifo "$logpipe"

function cleanup() {
  rm -rf "$logdir"
}
trap cleanup EXIT

# strace only read/write syscalls for the wrapped command (run in background)
# -f traces child processes too
sudo strace -fe trace=read,write -o "$logpipe" "$@" &

# This could be expanded to look at bytes written as well
grep read "$logpipe" | awk 'BEGIN {FS=") = "}{ sum += $2} END {print sum}'
echo "bytes read"