Hi,when I run my first shell script,I got something that doesn't work right.
I wrote this code in the script.
echo -e "Hello,World\a\n"
But the screen print like this:
-e Hello,World
The "-e" wasn't supposed to be printed out.
Can anyone help me out?:wall:
Many thanks!
What shell are you using?
(csh, ksh, bash, etc.)
Type:
man echo
See if "-e" is part of your "echo" command.
bash
I typed
#!/bin/bash
in the script
---------- Post updated at 11:49 AM ---------- Previous update was at 11:43 AM ----------
Yes, in the description it says
-e enable interpretation of backslash escapes
And when I type the command directly in the shell,it work right!
So weird!
[LEFT]More importantly which version of echo are you using
$ echo -e "cheeses \n\tCashel Blue\n\tRoquefort"
cheeses
Cashel Blue
Roquefort
$ which echo
/bin/echo
$ rpm -qf /bin/echo
coreutils-5.2.1-36.el4
In your shell and your script try
which echo
[/LEFT]
Mate, try
echo $SHELL
this will give which shell you are in.
Also Try
which bash
this will give the address for bash like "/usr/bin/bash"
add this to the first line of your script with shebang(#!).
In Bash "-e" option with echo should work.
Both of the command return /bin/bash
The reason I suggested
which echo
was to see if $PATH is different in your shell and your script. (eg you have a PATH setting in your shell which isn't exported to your script) if the command above returns different values for both then call the command in the script using the full path name returned in the shell, where it worked.
I try that and it turn out to return /bin/echo both
Plus,when I type
/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):
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):
type echo
Regards,
Alister
Both return echo is a shell builtin
Plus,when I type the command
echo --version
in bash it return
--version
when I type
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
$ shopt xpg_echo
Try setting xpg_echo mode off:
$ shopt -u xpg_echo
The first command return xpg_echo off
Thats a shame I could duplicate your issue by setting posix mode and xpg_echo:
$ set -o posix
$ shopt -s xpg_echo
$ echo -e testing
-e testing
Or
$ bash --posix -O xpg_echo
$ echo -e testing
-e testing
Perhaps your shell was compiled with --enable-strict-posix-default
I got the same output when I type the code above.
-e testing
And if my shell is using posix by default,when I type
echo -e
it should print -e ,right?
But it just print a blank line.
By the way,when I want to turn off the posix using set command,what should I type?
set +0 posix
to turn off
So is it correct that echo -e gives a blank line; but echo -e "Hello,World\a\n" gives:
-e Hello,World
echo -e "Hello,World\a\n" goes right when I type it in my bash,but goes wrong when I add it in my shell script.
Ah does the script have "#!/bin/sh" at the top, cause bash will go into posix mode if it's called with the name sh
I use #!/bin/bash in my script.
Plus,
bash firstscript.sh
output
Hello,World
sh firstscript.sh
output
-e Hello,World