how to use echo command to print out content of a text file?

Question

I am trying to figure out what is the usage of this command:

echo < a.txt

According to text book it should redirect a programs standards input. Now I am redirecting a.txt to echo but instead of printing the content of the file it is printing out one empty line! Appreciate if anyone display this behaviour.

Solution 1

echo doesn't read stdin so in this case, the redirect is just meaningless.

echo "Hello" | echo

To print out a file just use the command below

echo "$(<a.txt )"

Solution 2

In Unix, I believe all you have to do, assuming you have a file that isn't hefty is: cat <filename>

No echo required.

Comments

[M.Ionut]

Here for future reference: in my case, echo "$(<a.txt )" works with a bash shell (bash), but not with a Bourne shell (sh) - meaning that if you want this echo "$(<a.txt )" to work, you might need to have the first line of your script as #!/bin/bash instead of #!/bin/sh. Otherwise, it might not work.