This is a small utility that tries to print the current network usage to stdout. For continous monitoring, there is no need to run the tool over and over again, just use -m instead.

The tool reads the received and transmitted bytes from /sys/class/net/<iface> two times, with a small wait in between, then calculates the current network usage from the difference.

None, apart from standard libraries and gcc for compiling.

• Make sure gcc is installed
• Run the included build script

net-sysclass -I <interface> [OPTIONS...]

• -f FORMAT: format string for the output, see below; default is %c
• -g GRANULARITY: data unit to use (k for kbit, m for Mbit, etc); default is k
• -h: print usage information, then exit
• -i INTERVAL: seconds between probing for network usage; default is 1
• -I INTERFACE: (required) name of the network interface to monitor
• -k: keep printing, regardles of whether or not the ouput has changed
• -m: keep running and printing
• -p PRECISION: number of decimals to include in the output
• -r RATE: maximum throughput speed of the network interface in Mbps; default is 100
• -s: print a space between the value and unit
• -u: add the appropriate unit to the output (%, kbps, etc)
• -V: print version info and exit

• %r: received bytes (aka download), relative to interface max throughput (%)
• %t: transmitted bytes (aka upload), relative to interface max throughput (%)
• %c: combined bytes (aka up & down), relative to interface max throughput (%)
• %R: received bytes (aka download), absolute
• %T: transmitted bytes (aka upload), absolute
• %C: combined bytes (aka up & down), absolute

Show combined (up and down) network usage, in percent (relative to 100 Mbit), with two decimal digits and keep printing whenever there is a change:

net-sysclass -I $(ip -o -4 route show to default | awk '{print $5}') -mus -p2