For loop:
N=10
for i in $(seq 1 ${N}); do
echo ${i}
done
Count files in the current directory:
ls -l | wc -l
Infinite loop:
while :; do
echo "Looping..."
done
Multithreading:
sleep 1 &
echo "Hello" &
wait
Create foo text file from script:
cat > foo << EOF
Some
Text
Here
EOF
Read line by line:
while read line; do
echo ${line}
done < INPUT
Create a FIFO (named pipe):
mkfifo named_pipe
ls > named_pipe &
cat < named_pipe
rm named_pipe