Demo of reading stdin to a BASH script variable

read-stdin-to-variable.sh

#!/bin/bash

# Usage:
# echo 'hello!' | ./read-stdin-to-variable.sh

# https://stackoverflow.com/a/15269128

STD_IN=$(</dev/stdin)

echo "Echoing stdin:"
echo "$STD_IN"

echo "Echoing again:"
echo "$STD_IN"

to-snakecase.sh

#!/bin/bash

STD_IN=$(</dev/stdin)

echo $STD_IN | sed 's/-/_/g'

to-uppercase.sh

#!/bin/bash

STD_IN=$(</dev/stdin)

# https://stackoverflow.com/a/27480719
echo $STD_IN | awk '{print toupper($0)}'