bin/scp-resume.sh
2009-11-10 23:12:38 -08:00

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#!/bin/sh
#
# Speed improvements by using blocks by nitro.tm@gmail.com
#
# This script assumes that you have access to the 'dd' utility
# on both the local and remote host.
# dd transfer blocksize (8192 by default)
blocksize=8192
usage()
{
echo
echo "Usage: `basename $0` -u(pload) \$localfile \$remotefile [\$sshargs]"
echo " `basename $0` -d(ownload) \$remotefile \$localfile [\$sshargs]"
echo
echo " \$remotefile should be in the scp format, i.e.: [user@]host:filename"
echo " \$sshargs are option further ssh options such as a port specification"
echo " (-p 1234) or use of compression (-C)"
echo
echo " -u:"
echo " \$remotefile may be [user@]host: for uploading to your remote home directory"
echo " -d:"
echo " \$localfile may be a period (.) when downloading a remote file to the"
echo " current working directory."
echo
exit 1
}
[ -z "$1" -o -z "$2" -o -z "$3" ] && usage
option=$1
case $option in
-[uU]*)
localfile=$2
remote=$3
shift 3
sshargs="$*"
userhost=${remote%:*}
remotefile=${remote#*:}
if [ ! -f "$localfile" ]; then
echo "!! File not found: $localfile"
usage
fi
if [ x"$userhost" = x"$remote" ]; then usage; fi
if [ x"$remotefile" = x"$remote" -o -z "$remotefile" ]; then remotefile=`basename "$localfile"`; fi
echo "==>> Getting size of remote file:"
localsize=`ls -l "${localfile}" | awk '{ print $5 }'`
remotesize=`ssh $sshargs "$userhost" "[ -f \"${remotefile}\" ] && ls -l \"${remotefile}\"" | awk '{ print $5 }' `
[ -z "$remotesize" ] && remotesize=0
echo "=> Remote filesize: $remotesize bytes"
if [ $localsize -eq $remotesize ]; then
echo "=> Local size equals remote size, nothing to transfer."
exit 0;
fi
remainder=$((remotesize % blocksize))
restartpoint=$((remotesize - remainder))
blockstransferred=$((remotesize / blocksize))
echo "=> Resuming upload of '$localfile'"
echo " at byte: $restartpoint ($blockstransferred blocks x $blocksize bytes/block),"
echo " will overwrite the trailing $remainder bytes."
dd bs=$blocksize skip=$blockstransferred "if=${localfile}" | \
ssh $sshargs "$userhost" "dd bs=$blocksize seek=$blockstransferred of=\"$remotefile\""
echo "done."
;;
-[dD]*)
localfile=$3
remote=$2
shift 3
sshargs="$*"
userhost=${remote%:*}
remotefile=${remote#*:}
if [ x"$localfile" = x"." ]; then localfile=`basename "$remotefile"`; fi
if [ ! -f "$localfile" ]; then
localsize=0;
else
localsize=`ls -l "${localfile}" | awk '{ print $5 }'`
fi
[ x"$remotefile" = x"$remote" ] && usage
[ -z "$localsize" ] && localsize=0
remainder=$((localsize % blocksize))
restartpoint=$((localsize - remainder))
blockstransferred=$((localsize / blocksize))
echo "=> Resuming download of '$localfile'"
echo " at byte: $restartpoint ($blockstransferred blocks x $blocksize bytes/block)"
echo " filesize: $localsize; will overwrite the trailing $remainder bytes."
ssh $sshargs "$userhost" "dd bs=$blocksize skip=$blockstransferred \"if=${remotefile}\"" |
dd bs=$blocksize seek=$blockstransferred "of=$localfile"
;;
*)
usage
;;
esac