CODEWITHSUNDEEP
bashshellscriptingcentos
Anthony
Anthony

Reputation: 4050

Bash Echo Escape Sequences

I'm trying to write a bash script in CentOS that tests the various echo escape sequences. However, when I run the program

./test.sh a

I keep getting this error message:

bad interpretation: no such file or directory

Here is the script:

#! /bin/bash

# Test echo escape sequences

input=$1

case $input in
   a ) echo -e "\a" testing \a;;
   b ) echo -e "\b" testing \b;;
   c ) echo -e "\c" testing \c;;
   * ) echo Incorrect input
   exit 1;;
esac

Where did I go wrong?

EDIT: I'm running CentOS Minimal guest in VirtualBox on a Windows XP host

EDIT 2: 

 #! bin/bash

was in my script, not

#! /bin/bash

When I changed it to 

 #! /bin/bash

and run the program ./test.sh a, it just prints "a"

Upvotes: 2

Views: 3592

Answers (2)

user700390
user700390

Reputation: 2339

[EDIT] Based on the original post, this is usually caused by DOS LINE ENDINGS.

The CR in the CR/LF DOS line ending is being seen by the interpreter as part of the shell that should be used to execute the script.

So, it tries to load /bin/bash(CR) which does not exist, hence "bad interpreter" is displayed.

One easy way to correct this is to copy the contents of the script to the clipboard and then:

cat > test.sh (PASTE CLIPBOARD) (PRESS ENTER) (PRESS CTRL-D)

This will strip out any incorrect line endings (there are other ways to do it but this is a pretty easy / straight-forward solution.

Once the "bad interpreter" issue was resolved, another syntax error in the script is the use of "\a" when you probably intend '\a'.

[EDIT] I think I realize what you mean now. Try this instead:

echo -e '\a' testing '\\'a

Upvotes: 4

Adrian Cornish
Adrian Cornish

Reputation: 23858

Did you make the script executable with something like

   chmod 755 test.sh

Added

I wonder if part of the problem is the escape sequence you are using as they could mean \a=cursor up \b=cursor down \c=cursor forward.

Or also interpreted as \a=SOH Start of Heading \b=STX Start of Text or \c=ETX End of Text

Upvotes: 2

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