中国DOS联盟

How to insert a string at the beginning of a file? The requirement is that the inserted string does not contain carriage return and line feed.

I found that using echo always adds carriage return and line feed. For example, echo "hello" > file, the size of file is 7 bytes, and there is an extra carriage return and line feed at the end. How to solve this problem?

Use Horst's QECHO third-party tool.
------------------------------------------------------------------------
QECHO Quote echo Ver 1.3 (c) 2000 Horst Schaeffer
------------------------------------------------------------------------QECHO supports output that is not possible with the normal ECHO command: + Strings in 'single' or "double" quotes marks
+ ASCII byte values (decimal)
+ Control codes with caret, like ^L (=ASCII 12)
+ Symbols: CR (13), LF (10), FF (12), ESC (27)
+ @nn - write position (extra s.below)No terminating CR/LF is output unless specified (!) thus: QECHO "something" CR LF
is same as: ECHO somethingStrings may include the other type of quotes, like: 'file "%1" done'
or "file '%1' done". The same type of quotes must be doubled if used
within a string, for example: "file ""%1"" done".Pipes and redirections as usual. Separators (blank, comma, semicolon)
allowed. If any invalid data occur, the rest of the line will be ignored
(errorlevel > 0).Some examples:++ Write to a file without CR+LF QECHO "SET X="> some.bat++ Pipe multiple lines or CR's QECHO CR,"N",CR | format A: /q/u /v:"" (FORMAT, no prompts)
QECHO "D100,200",CR,"Q",CR | debug PROG.COM (DUMP thru DEBUG)++ Send control codes to printer (without CR/LF) QECHO FF > LPT1 (form feed)
QECHO ESC "@", ESC "l" 10 > LPT1 (reset, margin /EPSON)
Extra
-----
With the @-sign you can set the write position (1...) for the following
data. This allows column aligned output, even if the length of the first
part is variable.Example: Qecho "%varname%" @20 "more text", CR,LF >>file.extAnother feature: A string can be input to QECHO by redirection, an then
be completed by writing (or overwriting) something at the specified
position. Please test to find out if you can use it...----
QECHO is freeware by Horst Schaeffer - no warranties of any kind
eMail: horst.schaeffer@gmx.net= 04 AUG 2002
Use Google to search for the download address. Please write a good post title.

Thanks for the answer! May I ask if this function can be completed only using the original basic commands of DOS?

关于sercomm：
不用第三方工具的方法也有很多，比如下面的debug方法：

@echo off
:makeasd Generate debug script
for %%f in (~insert.*) do del %%f
for %%s in (e100"insert text"1a n~insert.txt rcx 10 w q) do echo %%s>>~insert.asd
:runscr Run debug script to generate prefix.txt
debug < ~insert.asd >nul
:fixed
copy ~insert.txt+%0 %0.txt > nul
for %%f in (~insert.*) do del %%f
:end

Re regarding sort: I've always been not very familiar with dubug. What does "1a" in "e100"insert text"1a" in the above program mean? Does it mean the end of the file? If the string is very long (exceeding 16 characters), do I need to modify the number after rcx accordingly to determine the length of the string written to the file?

Re Climbing:　　debug is a very good tool because it is included in all Microsoft operating systems, and it can be used to access hardware ports, memory system areas, and even dynamically assemble a small program. Mathematical operations and string operations can also be used with it. The 1a here is used as the end-of-text file character, mainly for copy /a to recognize, and can also be recognized by type. The reason here is to prevent the prefix string from being of an indefinite or undeterminable length. If the string is very long, the corresponding number needs to be modified. Generally, 100 is used as the length limit. Strings longer than this are no longer suitable for writing with the debug e command.

Is 1a just the character entered with Ctrl+z under the DOS command line? Thanks, I now also find that debug is really useful. It seems necessary to review the knowledge of assembly language again.

Re Climbing: Yes, not just 1a, all special characters from ASCII code 01 to 1a can be entered using Ctrl+A to Ctrl+Z. In the text environments of type (type con) and copy (copy con file), they are entered directly. In edit and most other DOS text editing environments, you also need to press Ctrl+P first.

First, extract the content of the first line and set it as a variable. Then use echo to write the prefix %variable%. Then use for /f "tokens=* skip=1" %%a in (old file) do echo %%a >> new file.

cmd @ xp