Command line args with spaces [duplicate]

Question

Invoking a shell script with command line arguments containing spaces is generally solved by enclosing the argument in quotes:

getParams.sh 'one two' 'foo bar'

Produces:

one two
foo bar

getParams.sh:

while [[ $# > 0 ]]
do
    echo $1
    shift
done

However, if a shell variable is first defined to hold the value of the arguments such as:

args="'one two' 'foo bar'"

then why does:

getParams.sh $args

not recognize the single quotes enclosing the grouped arguments? The output is:

'one
two'
'three
four'

How can I store command line arguments containing spaces into a variable so that when getParams is invoked, the arguments are grouped according to the quoted arguments just as in the original example?

The shell parses quotes (and escapes and a bunch of other things) before expanding variables, so putting quotes in variables isn't the same as using them directly on the command line. See BashFAQ #50: I'm trying to put a command in a variable, but the complex cases always fail! — Gordon Davisson
– Gordon Davisson, Commented Jul 6, 2018 at 7:45
[[ $# > 0 ]] does a string comparison. [[ $# -gt 0 ]] or (( $# > 0 )) or even while (($#)) — cdarke
– cdarke, Commented Jul 6, 2018 at 8:43

user000001 · Accepted Answer · 2018-07-06 14:31:39Z

2

Use an array:

args=('one two' 'foo bar')

getParams.sh "${args[@]}"

Using args="'one two' 'foo bar'" wont work, because the single quotes retain their literal value when inside double quotes.

To preserve multiple spaces in the arguments (and also handle special characters such as *), you should quote your variable:

while [[ $# -gt 0 ]]
do
    echo "$1"
    shift
done

edited Jul 6, 2018 at 14:31

answered Jul 6, 2018 at 7:43

user000001

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3 Comments

tgoneil Over a year ago

Thank you, @user000001. That mostly works. The remaining problem is that multiple spaces are replaced with one space. How do I preserve all the spaces if some strings have multiple adjacent spaces embedded?

user000001 Over a year ago

@tgoneil: You should quote the variable ("$1") to preserve multiple whitespaces in echo.

tgoneil Over a year ago

Ah ha! That did the trick! Thank you @user000001!

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