[speed test] Test ssh connection speed

scp-speed-test.sh

#!/bin/bash
# scp-speed-test.sh
# Author: Alec Jacobson alecjacobsonATgmailDOTcom
#   http://www.alecjacobson.com/weblog/?p=635
#
# Test ssh connection speed by uploading and then downloading a 10000kB test
# file (optionally user-specified size)
#
# Usage:
#   ./scp-speed-test.sh user@hostname [test file size in kBs]
#

ssh_server=$1
test_file=".scp-test-file"

# Optional: user specified test file size in kBs
if test -z "$2"
then
# default size is 10kB ~ 10mB
    test_size="10000"
else
    test_size=$2
fi


# generate a 10000kB file of all zeros
echo "Generating $test_size kB test file..."
`dd if=/dev/zero of=$test_file bs=$(echo "$test_size*1024" | bc) \
count=1 &> /dev/null`

# upload test
echo "Testing upload to $ssh_server..."
up_speed=`scp -v $test_file $ssh_server:$test_file 2>&1 | \
grep "Bytes per second" | \
sed "s/^[^0-9]*\([0-9.]*\)[^0-9]*\([0-9.]*\).*$/\1/g"`
up_speed=`echo "($up_speed*0.0009765625*100.0+0.5)/1*0.01" | bc`

# download test
echo "Testing download from $ssh_server..."
down_speed=`scp -v $ssh_server:$test_file $test_file 2>&1 | \
grep "Bytes per second" | \
sed "s/^[^0-9]*\([0-9.]*\)[^0-9]*\([0-9.]*\).*$/\2/g"`
down_speed=`echo "($down_speed*0.0009765625*100.0+0.5)/1*0.01" | bc`

# clean up
echo "Removing test file on $ssh_server..."
`ssh $ssh_server "rm $test_file"`
echo "Removing test file locally..."
`rm $test_file`

# print result
echo ""
echo "Upload speed:   $up_speed kB/s"
echo "Download speed: $down_speed kB/s"

Nice script! Although I wonder, what the heck is happening here:

($up_speed0.0009765625100.0+0.5)/1*0.01"

Nice script! Although I wonder, what the heck is happening here:

($up_speed_0.0009765625_100.0+0.5)/1*0.01"

That's a conversion from kibibyte to kilobyte. 1/1.024 is 0.9765625.

maybe better to replace

dd if=/dev/zero of=$test_file bs=$(echo "$test_size*1024" | bc) \

with

dd if=/dev/random of=$test_file bs=$(echo "$test_size*1024" | bc) \

because if compression is used, all zeros will significantly speed up the connection.

A good catch on randoms instead of zeros!

How to specify port and SSH key?

Random note:

Use /dev/urandom for generating random data. /dev/random blocks if there isn't enough entropy in the system (try and do cat /dev/urandom and see for yourself - and try moving your mouse randomly after it blocks). /dev/urandom is a pseudo-random number generator, so as long as it's seeded it can generate a virtually unlimited amount of random data.