Fetch file through a remote machine - A simple script

Here's a simple script that uses ssh to execute remote wget commands. Useful if your regular browsing connection is slow (but OK for just browsing) and you have another server with high speed connection for occasional downloads.

The script does the following:

• Takes a URL to download, remote machine id and user id on the remote machine.
• Runs remote pwd to get the working directory.
• Runs remote wget with the URL and captures the saved file name.
• Runs scp to copy the file to local system.
• Runs remote rm to remove the file from remote system.
• Deletes temporary files created.
  

Here's the script:

#!/bin/bash

# Replace the following with your server details.
# If you do not want password prompts setup authorized keys with following commands:
#     ssh-keygen -t rsa
#     cat ~/.ssh/id_rsa.pub | ssh @ 'cd .ssh; cat >> authorized_keys; chmod 600 authorized_keys'

remserver="<remote server>"
remuser="<remote user>"

if [ $# -lt 1 ]
then
echo "Usage: $0 <url>"
exit 1
fi

url=$1

echo "ssh ${remuser}@${remserver} 'pwd' >getthruremotedir" > ./getthrutmpscript
echo "remotedir=\`cat getthruremotedir\`" >> ./getthrutmpscript
echo "rm getthruremotedir" >> ./getthrutmpscript
echo "echo \"Got remotedir: \${remotedir}\"" >> ./getthrutmpscript

echo "ssh ${remuser}@${remserver} 'wget \"${url}\"' 2>&1 | grep \"saved\" | cut -d'\`' -f2 | cut -d\"'\" -f1 >getthrufilename" >> ./getthrutmpscript
echo "filename=\`cat getthrufilename\`" >> ./getthrutmpscript
echo "rm getthrufilename" >> ./getthrutmpscript
echo "echo \"Got filename: \${filename}\"" >> ./getthrutmpscript

echo "echo \"scp ${remuser}@${remserver}:\${remotedir}/\${filename} .\" > ./getthrutmpscript2" >> ./getthrutmpscript
echo "echo \"ssh ${remuser}@${remserver} 'rm -i \${remotedir}/\${filename}'\" >> ./getthrutmpscript2" >> ./getthrutmpscript
echo "chmod +x ./getthrutmpscript2" >> ./getthrutmpscript
echo "./getthrutmpscript2" >> ./getthrutmpscript
echo "rm ./getthrutmpscript2" >> ./getthrutmpscript

chmod +x ./getthrutmpscript
./getthrutmpscript
rm ./getthrutmpscript

If you do not want password prompts setup authorized keys with following commands:

ssh-keygen -t rsa
cat ~/.ssh/id_rsa.pub | ssh <user>@<machine> 'cd .ssh; cat >> authorized_keys; chmod 600 authorized_keys'

The script has worked fine for me, but use it carefully as it executes commands in remote system without any substantial output and error checks.