Shell Programming and Scripting

I try that and it turn out to return /bin/echo both

Plus,when I type

Code:

/bin/echo -e "Hello,world\a\n"

in the script ，it work right
Can you tell me why ?

What version of bash do you have? bash --version

Why are you even using echo -e?

Use printf instead.

Hi, Demon:

Amen to what scottn said. You'll see echo in many scripts so you should be familiar with it, but echo with any options is not portable. Do yourself a favor and learn your way around the printf(1) command (usually a shell-builtin).

Regarding your problem, perhaps your environment has aliased echo or has defined a function that overrides the builtin. In bash, the following command would indicate exactly what your shell is trying to execute (whether you type it at the command line or in a script):

Code:

type echo

Regards,
Alister

---------- Post updated at 04:05 PM ---------- Previous update was at 03:58 PM ----------

When the first word contains slashes, the shell attempts to execute the executable at that location; when the first word does not contain slashes, the shell goes through a lookup process that checks for the existence of functions and builtins before it tries a $PATH lookup. In either case, aliases are expanded beforehand.

Regards,
Alister

GNU bash, version 4.1.5(1)-release (i686-pc-linux-gnu)

---------- Post updated at 08:09 PM ---------- Previous update was at 07:53 PM ----------

Regarding your problem, perhaps your environment has aliased echo or has defined a function that overrides the builtin. In bash, the following command would indicate exactly what your shell is trying to execute (whether you type it at the command line or in a script):

Code:

type echo

Regards,
Alister

Both return echo is a shell builtin

Plus,when I type the command

Code:

echo --version

in bash it return

--version

when I type

Code:

echo --help

int bash it return

--help

But when I type /bin/echo instead of echo,everything goes right.

Anything difference between the builtin echo and the /bin/echo?

Perhaps you have posix mode and xpg_echo set?

What output do you get from

Code:

 $ shopt xpg_echo

Try setting xpg_echo mode off:

Code:

$ shopt -u xpg_echo

The first command return xpg_echo off