UNIX for Dummies Questions & Answers

Hello,

So I have approximately 300 files of raw data (.txt) files that I am using to perform statistical analysis. I have been able to construct a Fortran program that is able to perform my statistical analysis on a file by file basis.

However, I now want to be able to loop program through all of the text files through the use of a shell script, rather than going running the program ~300 times which is not realistic.

I'm thinking about performing some sort of a Do Loop in the terminal to loop through the program with for each file. However, I do not know how to change my fortran program such that I can replace the name of the file to open/write to.

Any help would be greatly appreciated.

Thanks

If you can have your fortran program read from standard input and write to standard output, then it will be easily automated. Just redirect into and out of the program.

Your program may become actually simpler; no file-opening code at all

Code:

for FILE in *.txt
do
        ./myprogram < "$FILE" > "$FILE.out"
done

Assuming your fortan code can handle arguments...

Code:

for FILE in *.txt; do fortran_progname ${FILE}; done

Thanks for the help, I'll mess around with it for a little bit.

So "$FILE" serves as the name of the text file. So in my Fortran program would I have to put $File where I am attempting to open the txt files? That way we are running the program through with each respective txt file?

No. The shell will evaluate the variable $FILE and perform Variable Expansion to convert the variable into the actual filename.

If your program can handle arguments, the code would then use Parameter Expansion to evaluate the 1st, 2nd, 3rd argument, etc...

You absolutely shouldn't use the variable $FILE in your fortran code, unless it is defined explicitly.

Also note that shell variables are case sensitive, and that $FILE is NOT the same as $File

How do you execute the fortan program for a single file ??

Well I currently just have a basic OPEN statement of the form

OPEN (10,file='389534ascii_vF.txt',status='old')

Then simply read in the data and perform calculations and then output it.

Compile it using
gfortran filename.f90 -o filename.o
Run
./filename.o

Is that what you were wondering?

Well, yes. It has been 6-8 yrs since I have read any fortran code, but I believe arguments or parameters are not valid.

I would follow up on Corona688's suggestion of modifying the program to accept standard input and output. Otherwise sorry, over my head.