How to fix scp: error: unexpected filename: in SSH

Prefix filenames and paths with ./ to make them explicit relative paths. This prevents SCP from misinterpreting special characters like colons.

# Instead of:
scp file:name.txt user@host:/tmp/

# Use:
scp ./file:name.txt user@host:/tmp/

# For wildcard copies:
scp ./* user@host:/tmp/

The ./ prefix explicitly marks the path as a file, not a remote host specification.

If you're using . as the destination (current directory), replace it with the full path or $(pwd) (print working directory).

# Instead of:
scp user@host:/path/to/file .

# Use absolute path:
scp user@host:/path/to/file /home/user/target/

# Or use $(pwd):
scp user@host:/path/to/file $(pwd)/

This is particularly important with OpenSSH versions that have the CVE-2018-20685 fix.

If filenames contain spaces, colons, or other special characters, ensure they are properly quoted or escaped.

# For files with spaces:
scp "user@host:/path/to/file name.txt" ./

# For files with colons (using relative path):
scp user@host:/path/to/./file:name.txt ./

# Double-check the exact filename on remote:
ssh user@host ls -la /path/to/file*

If you trust the remote server and need a quick workaround, use the -T flag to disable strict filename validation.

scp -T user@host:/path/to/file ./

Warning: Only use this when you fully trust the remote host, as it disables security validations. This should be a temporary measure while you fix the underlying issue.

If SCP continues to cause issues, use SFTP (SSH File Transfer Protocol) instead, which doesn't have the same filename validation restrictions.

sftp user@host << EOF
get /path/to/file
bye
EOF

SFTP is more modern, more reliable, and handles special characters better than legacy SCP.