Today I needed to write a Ruby script to fetch a file using SCP. I thought it would be nice if it also displayed a "percent complete" counter as it went. This is what I came up with.
require 'rubygems'
require 'net/scp'
puts "Fetching file"
# Establish the SSH session
ssh = Net::SSH.start("IP Address", "username on server", :password =>"user's password on server", :port => 12345)
# Use that session to generate an SCP object
scp = ssh.scp
# Download the file and run the code block each time a new chuck of data is received
scp.download!("path/to/file/on/server/fileName", "/Users/me/Desktop/") do |ch, name, received, total|
# Calculate percentage complete and format as a two-digit percentage
percentage = format('%.2f', received.to_f / total.to_f * 100) + '%'
# Print on top of (replace) the same line in the terminal
# - Pad with spaces to make sure nothing remains from the previous output
# - Add a carriage return without a line feed so the line doesn't move down
print "Saving to #{name}: Received #{received} of #{total} bytes" + " (#{percentage}) \r"
# Print the output immediately - don't wait until the buffer fills up
STDOUT.flush
end
puts "Fetch complete!"