Question

I am trying to write a shell program that will search my current directory (say, my folder containing C code), read all files for the keywords “printf” or “fprintf”, and append the include statement to the file if it isn’t already done.

I have tried to write the search portion already (for now, all it does is search files and print the list of matching files), but it is not working. Included below is my code. What am I doing wrong?

EDIT: New code.

#!/bin/sh
#processes files ending in .c and appends statements if necessary

#search for files that meet criteria
for file in $( find . -type f )
do
    echo $file
    if grep -q printf "$file"
    then
        echo "File $file contains command"
    fi
done

Answer 1

To execute commands in a subshell you need $( command ). Notice the $ before the parenthesis.

You don’t need to store the list of files in a temporary variable, you can directly use

for file in $( find . ) ; do
    echo "$file"
done

And with

find . -type f | grep somestring

you are not searching the file content but the file name (in my example all the files which name contains “somestring”)

To grep the content of the files:

for file in $( find . -type f ) ; do
  if  grep -q printf "$file" ; then
    echo "File $file contains printf"
  fi
done

Note that if you match printf it will also match fprintf (as it contains printf)

If you want to search just files ending with .c you can use the -name option

find . -name "*.c" -type f

Use the -type f option to list only files.

In any case check if your grep has the -r option to search recursively

grep -r --include "*.c" printf .