scp: Do not Overwrite Existing File On Linux or Unix System

in Categories , , , last updated May 10, 2013

I am a new Linux user. I use scp to upload files to net-storage provided CDN company. I do not want to overwrite the existing files. How can I prevent overwriting of files when using scp command under Linux, Mac OS X or Unix like operating systems?

Short answer – Not possible.

Long answer

The scp command will always overwrite the already present files if owner has write permissions. I suggest that you use the rsync command. The syntax is

rsync --ignore-existing file1 user@server1:/dest/
rsync --ignore-existing
### add ssh, just in case ;) ###
rsync -e ssh --ignore-existing
rsync -avP --ignore-existing *.png
rsync --ignore-existing file1 /path/to/dest/

The --ignore-existing option skip updating files that exist on receiver such as

Shell script example

The following script will upload files from your computer to the remote server using the rsync command. First, make sure you setup the public key authentication:

# Purpose: Batch file uploader from my desktop to the remote server
# Author: nixCraft <> under GPL v2.x+
# -----------------------------------------------------------------
## static url mapping ##
## rsync args ##
_args="-aPv --ignore-existing"
## fail safe ##
[[ "$_files" == "" ]] && { echo "Usage: $0 file1.png file2.png"; exit 0; }
## Let us start uploading files. Bash for loop allows us to do a few more additional things, 
## but I am keeping it simple here for demo purpose
for i in $_files
        # make sure $i file exist #
        if [ -f "$i" ]
                rsync "$_args" "$i" ${_user}@${_server}:${_dest}
                echo "Error $i file not found."
if [ $_isuploaded -eq 1 ]
        echo "CDN urls:"
        echo -e "$_cdnurls"

You can use the script as follows:

./script foo.png
./script foo.png bar.png
./script *.mov
./script test.gif

Sample outputs:

sending incremental file list
         950 100%    0.00kB/s    0:00:00 (xfer#1, to-check=0/1)
sent 1053 bytes  received 31 bytes  197.09 bytes/sec
total size is 950  speedup is 0.88
CDN urls:

Run it again:

./script test.gif

Sample outputs:

sending incremental file list
sent 60 bytes  received 12 bytes  13.09 bytes/sec
total size is 950  speedup is 13.19
CDN urls:
See also

If anyone knows a better solution to this FAQ please share in the comments below.

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

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