this should be a discussion or search about the possible and allowed characters in a for-loop.
As Dave showed at DOS batch script to parse CSV file and output a text file.
The current list seems to exclude only the batch delimiters.
dbenham wrote:The following is a summary of characters that have restrictions or require special syntax.
Note that text within angle brackets like <space> represents a single character.
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Dec Hex Character Define Access
0 0x00 <nul> No No
09 0x09 <tab> No %%^<tab> or "%%<tab>"
10 0x0A <LF> No %%^<CR><LF><CR><LF> or %%^<LF><LF>
11 0x0B <VT> No %%<VT>
12 0x0C <FF> No %%<FF>
13 0x0D <CR> No No
32 0x20 <space> No %%^<space> or "%%<space>"
34 0x22 " %%^" %%" or %%^"
37 0x25 % %%%% No
38 0x26 & %%^& %%^& or "%%&"
41 0x29 ) %%^) %%^) or "%%)"
44 0x2C , No %%^, or "%%,"
59 0x3B ; No %%^; or "%%;"
60 0x3C < %%^< %%^< or "%%<"
61 0x3D = No %%^= or "%%="
62 0x3E > %%^> %%^> or "%%>"
94 0x5E ^ %%^^ %%^^ or "%%^"
124 0x7C | %%^| %%^| or "%%|"
126 0x7E ~ No %%~~ (%%~ may work, or may crash COMMAND.EXE)
255 0xFF <NB space> No No
dbenham wrote:Special characters like ^ < > | & must be either escaped or quoted. For example, the following works:
for /f %%^< in ("OK") do echo "%%<" %%^<
Some characters cannot be used to define a FOR variable. For example, the following gives a syntax error:
for /f %%^= in ("No can do") do echo anything
But %%= can be implicitly defined by using the TOKENS option, and the value accessed in the DO clause like so:
for /f "tokens=1-3" %%^< in ("A B C") do echo %%^< %%^= %%^>
The % is very odd - You can define a FOR variable using %%%%. The value cannot be accessed, yet the subsequent tokens work fine.
for /f "tokens=1,2" %%%% in ("A B") do echo %%%% %%^&
The above yields %% B
The ~ is a dangerous FOR variable. It can only be defined indirectly. But you also have to be careful how you access it. If you attempt to access the variable using %%~, you may get the correct result, you may get the wrong result, or you may crash COMMAND.EXE! The only reliable way to access it is using %%~~, but it strips any enclosing quotes as would be expected.
for /f "usebackq tokens=1,2" %%} in ('"A" "B"') do echo %%} %%~~
The above yields "A" B
My own results are:
The ~ CAN be defined by
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for %%~ in ("Hello") do echo %%~!%%~ is dangerous only at the end of a line, as it can produce buffer overruns.
But the same could be useful for viewing the internal token buffer.
Once I build a nice trick with this.
Currently I'm searching for the example!
The %%%% can be accessed with a simple trick, you need the ~
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for %%%% in ("Hello") do echo %%~%%In my tests you could also use as the define parameter.
10 0x0A <LF>
11 0x0B <VT>
12 0x0C <??>
But also here I can't remember how I tested it
jeb
