Computer Hope
Microsoft => Microsoft DOS => Topic started by: houseofthesun1 on January 30, 2010, 10:15:14 PM
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The command
copy c:\SAMPLE_TRILLIUM_DIRECTORY\BR_Status_list*.csv c:\SAMPLE_TRILLIUM_DIRECTORY\BR_Status_List.csv /Y
copies several files into one file, but at the end there is a blank line with the word SUB.
Is SUB a control character?
The only other control chars I see are CR and LF....which is of course not a problem
Thanks in advance for any help regarding this problem!
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SUB is a control character; ASCII 26 decimal, 1A hex, also called Control-Z. It is appended by the copy command in text (default) mode. To avoid it use copy with the /b (binary) switch.
copy /b c:\SAMPLE_TRILLIUM_DIRECTORY\BR_Status_list*.csv c:\SAMPLE_TRILLIUM_DIRECTORY\BR_Status_List.csv /Y
Dec Hex Unicode Char Name
0 00 U+0000 NUL Null
1 01 U+0001 STX Start of Header
2 02 U+0002 SOT Start of Text
3 03 U+0003 ETX End of Text
4 04 U+0004 EOT End of Transmission
5 05 U+0005 ENQ Enquiry
6 06 U+0006 ACK Acknowledge
7 07 U+0007 BEL Bell
8 08 U+0008 BS BackSpace
9 09 U+0009 HT Horizontal Tabulation
10 0A U+000A LF Line Feed
11 0B U+000B VT Vertical Tabulation
12 0C U+000C FF Form Feed
13 0D U+000D CR Carriage Return
14 0E U+000E SO Shift Out
15 0F U+000F SI Shift In
16 10 U+0010 DLE Data Link Escape
17 11 U+0011 DC1 Device Control 1 (XON)
18 12 U+0012 DC2 Device Control 2
19 13 U+0013 DC3 Device Control 3 (XOFF)
20 14 U+0014 DC4 Device Control 4
21 15 U+0015 NAK Negative acknowledge
22 16 U+0016 SYN Synchronous Idle
23 17 U+0017 ETB End of Transmission Block
24 18 U+0018 CAN Cancel
25 19 U+0019 EM End of Medium
26 1A U+001A SUB Substitute
27 1B U+001B ESC Escape
28 1C U+001C FS File Separator
29 1D U+001D GS Group Separator
30 1E U+001E RS Record Separator
31 1F U+001F US Unit Separator
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Thanks SO MUCH for your help !!! :) (|
By the way, the /b worked when I put it on the end of the command (for the destination file).
I have another question.
Even now when I requested "binary" mode, the CR LF control characters still appear (that is a good thing!)
Aren't they ascii control characters also?
What is this control-z character for in the first place?
When would I ever want to have the character at the end of my text?
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Thanks SO MUCH for your help !!! :) (|
By the way, the /b worked when I put it on the end of the command (for the destination file).
I have another question.
Even now when I requested "binary" mode, the CR LF control characters still appear (that is a good thing!)
Aren't they ascii control characters also?
What is this control-z character for in the first place?
When would I ever want to have the character at the end of my text?
the "EOF marker" (ctrl-Z) is a holdover from CP/M; with CP/M, files could only be allocated in blocks the size of a disk sector. Because of that, it was necessary to indicate where the data actually ended. To do this, programs padded off the unused space in the last sector of a file with EOF marks (Ctrl-Z). when they read the file, they would read until they found an EOF mark and then stop.
DOS kept the convention only for convenience with porting CP/M applications, by tradition text files all end with an EOF mark, and copy honours this.
Note that /B treats the data as binary data, and therefore copies all of it; the extra eof mark you see without the /B switch is copy treating it as a text file and appending the EOF marker as a sort of convenience to programs that read until an EOF marker rather then the real end of file. Also, note that using copy to append two files, as in "copy file1+file2 resultfile" will not work properly without the /b switch in some circumstances; for example, if you try to combine two files that are non-text files or contain EOF markers within the text. Copy only copies each file until it finds an EOF mark, and writes them to the new file.
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Thanks for sharing your knowledge!!
I look forward to helping others too!
:D