linux - Save Bash Shell Script Output To a File with a String -

i have executable takes file , outputs line. running loop on directory:

for file in $directory/*.png         ./eval $file >> out.txt done

the output of executable not contain name of file. want append file name each output.

edit1

perhaps, not explain correctly want name of file , output of program well, processing same file, doing following

for file in $directory/*.png          echo -n $file >> out.txt      or      printf "%s" "$file" >> out.txt      ./eval $file >> out.txt done

for both new line inserted

if understood question, want is:

then i'd suggest composing single line of text (using echo), comprising:

the name of file, $file part,
...followed separator, may not need may further processing of result. used ":". can skip part if not interesting you,
...followed output of program processing file: $(...) construct

echo $file ":" $(./eval $file) >> out.txt

...and appending line of text file, got part right.

Guide