IF-ERRORLEVEL usage

IF-ERRORLEVEL

Create TEST4.BAT with the following content:
@ ECHO OFF
Xcopy c: \ AUTOEXEC. bat d :\
If errorlevel 1 ECHO file copy failed
If errorlevel 0 ECHO, the file is successfully copied.
Then execute the file:
C: \> TEST4
If the file is successfully copied, the screen displays "successfully copied file"; otherwise, the screen displays "file copy failed ".
If errorlevel is used to test the return value of the previous DOS command. Note that it is only the return value of the previous command, and the return value must be determined in order from large to small.
Therefore, the following batch file is incorrect:
@ ECHO OFF
Xcopy c: \ AUTOEXEC. bat d :\
If errorlevel 0 ECHO, the file is successfully copied.
If errorlevel 1 ECHO does not find the copy object
If errorlevel 2 ECHO, the user uses ctrl-c to stop the copy operation.
If errorlevel 3 ECHO preset Error Blocking file copy operation
If errorlevel 4 ECHO disk write error during copy process
Whether the copy is successful or not, the following:
Copy file not found
You can use ctrl-c to stop the copy operation.
Preset errors prevent file copy operations
An error occurred while writing the disk during the copy process.
Are displayed.
The return values of several common commands and their meanings are as follows:
Backup
0 successfully backed up
1 backup file not found
2. File Sharing conflicts prevent backup from being completed
3. Use ctrl-c to stop the backup.
4. the backup operation is aborted due to a fatal error.
Diskcomp
0 disks are the same
1 disk is different
2. You can use ctrl-c to stop the comparison operation.
3. The comparison operation is aborted due to a fatal error.
4 preset error abort comparison
Diskcopy
0 disk copy operation successful
1 non-fatal disk read/write error
2. You can use ctrl-c to end the copy operation.
3. the disk copy is aborted due to a fatal processing error.
4. The copy operation is blocked due to a preset error.
Format
0: formatted successfully.
3. Use ctrl-c to stop formatting.
4. The format is aborted due to a fatal processing error.
5. When "proceed with format (y/n)?" is displayed )?" End with user input n
Xcopy
0 successfully copied the file
1 copy file not found
2. You can use ctrl-c to stop the copy operation.
4. preset errors prevent file copy operations
5. An error occurred while writing the disk during the copy process.