How do you write data to a file that does not yet exist using the terminal?

# Create an empty file "filename.txt" or clear an existing one
> filename.txt

# Write "text string" to the file "filename.txt". If the file does not exist, it will be created.
# If the file exists, its contents will be overwritten.
echo "text string" > filename.txt

# Append "text string" to the end of the file "filename.txt". If the file does not exist, it will be created.
echo "text string" >> filename.txt

# Write the contents of the file "input.txt" to the file "output.txt". If "output.txt" does not exist, it will be created.
# If "output.txt" exists, its contents will be overwritten.
cat input.txt > output.txt

# Write the contents of the file "input.txt" to the end of the file "output.txt". If "output.txt" does not exist, it will be created.
cat input.txt >> output.txt