Some examples of iterating through files and looping through file content in Bash. For details, see the Bash man page or the Bash reference manual.
Loop Through Files
for FILE in *; do
# do something with $FILE
echo "File: $FILE"
done
For more control, use /usr/bin/file
for FILE in $(find ./ -name *.html -type f); do
# do something with $FILE
echo "HTML File: $FILE"
done
Loop Through Lines in a File
while read LINE; do
# do something with $LINE
echo "Line: $LINE"
done < /etc/hosts
Loop Through Words in a File
for WORD in $(cat /etc/hosts); do
# do something with $WORD
echo "Word: $WORD"
done
Loop Through Characters in a File
while read -n1 CHAR; do
# do something with $CHAR
echo "Character: $CHAR"
done < /etc/hosts