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Full Discussion: Bash scripting, question about a variable
Top Forums Shell Programming and Scripting Bash scripting, question about a variable Post 302414302 by cfajohnson on Monday 19th of April 2010 08:33:10 PM
Old 04-19-2010
Quote:
Originally Posted by bakunin
The statement is poorly phrased, btw., because it is asking for troubles: the asterisk ("*") has a special meaning to the shell and to protect such special characters from being interpreted one should cover them in quotes:

Code:
DIR="$1/*"


It is not necessary to quote an assignment unless it contains literal whitespace.
Quote:
Furthermore, when using variable-names without spaces surrounding them it is a wise precaution to explicitly mark what belongs to the variable identifier and what doesn't:

Code:
DIR="${1}/*"


There's no point to using braces when the name is followed by a character that cannot be contained in a variable name.
Quote:
In your case this makes no difference, but consider:

Code:
a="blabla"
b="$ab"     # appending "b" will not work, because a variable named "ab" is expected
echo "$b"

b="${a}b"  # this will work
echo "$b"

I hope this helps.

bakunin
Last edited by cfajohnson; 04-20-2010 at 02:54 AM..
 

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LEARN ABOUT DEBIAN

printwait

MESSAGES(3)						  libbash messages Library Manual					       MESSAGES(3)

NAME

     messages -- libbash library that implements a set of functions to print standard status messages

SYNOPSIS

     printOK	 [indent]
     printFAIL	 [indent]
     printNA	 [indent]
     printATTN	 [indent]
     printWAIT	 [indent]

DESCRIPTION

   General
     messages is a collection of functions to print standard status messages - those [ OK ] and [FAIL] messages you see during Linux boot process.

     The function list:
	   printOK	    Prints a standard [ OK ] message (green)
	   printFAIL	    Prints a standard [FAIL] message (red)
	   printNA	    Prints a standard [ N/A] message (yellow)
	   printATTN	    Prints a standard [ATTN] message (yellow)
	   printWAIT	    Prints a standard [WAIT] message (yellow)

     Detailed interface description follows.

   indent
     Column to move to before printing.

     Default indent is calculated as TTY_WIDTH-10. If current tty width can not be determined (for example, in case of serial console), it
     defaults to 80, so default indent is 80-10=10

FUNCTIONS DESCRIPTIONS

   printOK [indent]
     Prints a standard [ OK ] message (green)

   printFAIL [indent]
     Prints a standard [FAIL] message (red)

   printNA [indent]
     Prints a standard [ N/A] message (yellow)

   printATTN [indent]
     Prints a standard [ATTN] message (yellow)

   printWAIT [indent]
     Prints a standard [WAIT] message (yellow)

EXAMPLES

     Run a program named MyProg, and report it's success or failure:

	      echo -n 'Running MyProg...'
	      printWAIT
	      if MyProg ; then
		      printOK
	      else
		      printFAIL
	      fi

AUTHORS

     Hai Zaar <haizaar@haizaar.com>
     Gil Ran <gil@ran4.net>

SEE ALSO

     ldbash(1), libbash(1)

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