Mysterious behavior of echo command

Question

When we need to use escape sequence characters with echo command we must use the -e option. Like

echo -e "Enter your name : \c"

But when we include such kind of statements inside a shell program (.sh file), it produces a mysterious error. It prints

-e Enter your name : 

It doesn't need that -e option with echo command as if we write like this

echo "Enter your name : \c"

It shows output with no errors, but that doesn't work in shell.

So what is the reason? I am using bash shell and Ubuntu 15.04 version.

Answer 1

I guess you haven't used a shebang (#! /bin/bash as the first line of your script). In that case, the script is run using /bin/sh, which is /bin/dash. And echo in dash doesn't support the non-standard -e (have a look at the POSIX standard). You really shouldn't use echo -e. Use printf instead for far more portable behaviour. See Why is printf better than echo`? on Unix and Linux. The following commands should behave identically:

bash -c 'printf "%s" "Enter your name"'
dash -c 'printf "%s" "Enter your name"'