中国DOS联盟

i want to know how to use dos command to output a file (Ofile) from another file (Ifile) by extracting specific records. The records to be extracted are those records where character position 10 to 12 (in Ifile) has a value of '123'

For example: Ifile have 3 records which are:

ABCDFG123RTE
DRSERF234TEF
ADASSD123RTZ

So now i want to extract the record which from postion 7- 9 hav value 123 into Ofile, so from this case, Ofile will output two records which are:ABCDFG123RTE and ADASSD123RTZ

Maybe C or QBASIC is a better choice to solve the problem...

[ Last edited by fdsiuha on 2005-10-27 at 17:59 ]

If the character are not position specific, you can use external command FIND

For example: find "123" Ifile > Ofile

If the character are not case sensitive you can use /i paramater

For example: find/i "abc" Ifile > Ofile
will find the line that contain "abc" "ABC" "Abc" "ABc" ......

If you need the character are position specific, I recommend you use 4DOS as command interpreter (the 4DOS 7.50 is freeware now,you can download it from official website http://www.jpsoft.com or ftp://jpsoft.com. and should be used in DOS and Win9X environment)

you can use its' Variable Function @INSTR

usage:

@INSTR: Returns a substring, starting at the position start and continuing for length characters. If the length is omitted, it will default to the remainder of the string. If the length is negative, the start is relative to the right side of the string. The first character in the string is numbered 0; if the length is negative, the last character is numbered 0.

For example, %@INSTR gets the current time and extracts the
hour; %@INSTR extracts the seconds. If the string includes
commas, it must be quoted with double quotes or back-quotes . The
quotes do count in calculating the position of the substring.

If your record of Ifile are left aligned on each line, you try do this

for %f in (@Ifile) do if %@INSTR==123 echo %f >>Ofile

Thanks for you all replies, the information very usefull for me.
Ok, i try to do it.
Thanks a lot.

for %f in (@Ifile) do if %@INSTR==123 echo %f >>Ofile

what is %f stand for, just now i try to do the testing but seem like it not work?

thanks.

Best Regards,
Libbyooi

"%f" is the variable to be used in the FOR command. it can be named in any character(s) by you, in other word, it is a variable name only. %a %b %c %abc etc. are valided.

according to your example, I creat a file named "Ifile" that contain the following:

ABCDFG123RTE
DRSERF234TEF
ADASSD123RTZ

and then I execute the command:

for %f in (@ifile) if %@instr==123 echo %f>>ofile

the result Ofile is:

ABCDFG123RTE
ADASSD123RTZ

Please note, the paramater of starting at the position is 6. The %f and %%f are equal.

by the way, I am not good at English. If you can understand Chinese, I prefer discuss this question with you in Chinese.

[ Last edited by DOSforever on 2005-10-28 at 12:00 ]