COPY

Copy one or more files to another location.

Syntax
      COPY [options] [/A|/B] source [/A|/B] [+ source2 [/A|/B]...] [destination [/A|/B]]

      COPY source1 + source2.. destination [options]

Key
     source :  Pathname for the file or files to be copied.

        /A  :  ASCII text file (default)
        /B  :  Binary file copy - will copy extended characters.
        /D  :  Allow the destination file to be created decrypted.

destination :  Pathname for the new file(s).

        /V  :  Verify that the destination file, once written, can be read.
               No comparison with the source files occurs. 

        /N  :  If at all possible, create only short filenames (8.3) in the
               destination. This option can help when copying between disks
               that are formatted differently e.g NTFS and VFAT, or when archiving 
               data to an ISO9660 CDROM.

        /L  :  If source is a symbolic link copy the link to the target
               instead of the actual file the source link points to.

        /Y  :  Suppress confirmation prompt, when overwriting files.

        /-Y :  Enable confirmation prompt, when overwriting files.

        /Z  :  Copy files in restartable mode. If the copy is interrupted
               part way through, it will restart if possible. (use on slow networks)

Combining files

To combine files, specify a single file for the destination, but multiple files as the source. To specify more than one file use wildcards or list the files with a + in between each (file1+file2+file3)
When copying multiple files in this way the first file must exist or else the copy will fail, a workaround for this is COPY null + file1 + file2 dest1

Binary copies

"COPY /B ... " will copy files in binary mode.

The /A and /B options can appear in multiple locations, with different meanings depending on location.
Before any source - they will set the default mode for all source and destination files.
After a source - they will set the mode for that source.
After the destination - they will set the mode for the destination.

Copy from the console (accept user input)

COPY CON filename.txt
Then type the input text followed by ^Z (Control key & Z)

To do this in Powershell use the following function:

function copycon {
[system.console]::in.readtoend()
}

Prompt to overwrite destination file

Under Windows 2000 and above, the default action is to prompt on overwrite unless the command is being executed from within a batch script.
To force the overwriting of destination files use the COPYCMD environment variable:
SET COPYCMD=/Y

Errorlevels

If the file(s) were successfully copied %ERRORLEVEL% = 0
If the file was not found or bad parameters given = 1

COPY will accept UNC pathnames

Examples:

Copy a file in the current folder
COPY source_file.doc newfile.doc

Copy from a different folder/directory:
COPY "C:\my work\some file.doc" "D:\New docs\newfile.doc"

Specify the source only, with a wildcard will copy all the files into the current directory:
COPY "C:\my work\*.doc"

Specify the source with a wildcard and the destination as a single file, this is generally only useful with plain text files.
COPY "C:\my work\*.txt" "D:\New docs\combined.txt"

Quiet copy (no feedback on screen)
COPY source_file.doc newfile.doc >nul

Copy a file, but do not overwrite if the destination file already exists, this technique only works for a single file, no wildcards:

Echo n|COPY /-y c:\demo\source_file.txt c:\dir\dest.txt

COPY is an internal command.

“Success seems to be connected with action. Successful men keep moving. They make mistakes, but they don’t quit” ~ Conrad Hilton

Related:

ROBOCOPY - Robust File and Folder Copy.
XCOPY - Copy files and folders.
MOVE - Move a file from one folder to another.
Q126457 - VERIFY ON, COPY /V, XCOPY /V commands do not compare data.
PowerShell equivalent: Copy-Item - Copy an item from one location to another.
Equivalent bash command (Linux): cp - Copy one or more files to another location.