How do we check if a command line argument to a shell script is within quotes?

Question

How to I get a corresponding shell command for the following batch command :

    if %1 EQU %~1 (
        echo ERROR ! The username must be within quotes.
    )

please clarify your question with an exact sample of calling your quote_Verify script. Unix shell people don't typically know all of the 'options' that bat cmds provide, especially %~1. Good luck. — shellter
– shellter, Commented May 9, 2012 at 14:22
I am calling the batch script as follows: test.bat "username" %~1 expands %1 removing any surrounding quotes (") — Pradeep Vairamani
– Pradeep Vairamani, Commented May 9, 2012 at 17:06

l0b0 · Accepted Answer · 2012-05-09 13:41:34Z

3

Quotes in Bash are syntactic, not literal, so they are not seen at all in the script. AFAIK there is absolutely no way for a script to know whether or how the parameters were quoted, because any quotes are effectively gone by the time the script receives the parameters.

If you want to check whether the parameter contains whitespace or other special characters which would make it "amenable" to quoting in Bash, you can check whether the "Bash-quoted" string is equal to the original string:

[[ "$1" = "$(printf %q "$1")" ]]

If you want to check whether the parameter was literally quoted, you could do a simple check like

[[ "$1" =~ ^\".*\"|\'.*\'$ ]]

That said, why would you ever need this?

answered May 9, 2012 at 13:41

l0b0

59.6k32 gold badges155 silver badges247 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Pradeep Vairamani Over a year ago

One use case is to parse the options from shell script command line. Eg. ./test.sh -u <username> -b <path> -c <abc> If the user fails to specify a username, the script would incorrectly take the next option flag as the username. I could use getopts but I wanted it to be as consistent as possible with the corresponding batch script. Another possible solution would be to make sure that the user is not equal to any of the option flags, but that seemed like a more tedious approach.

Aaron Digulla · Accepted Answer · 2012-05-09 12:07:30Z

1

With bash, try this:

if [[ -z "$1" ]]; then
    echo ERROR ! The username must be within quotes.
fi

answered May 9, 2012 at 12:07

Aaron Digulla

330k111 gold badges625 silver badges840 bronze badges

1 Comment

shellter Over a year ago

it the O.P. meant that $1=\"AString\", your test didn't work for me. It will accept any string as correct, and only an empty $1 as the error. Good luck to all!

Collectives™ on Stack Overflow

How do we check if a command line argument to a shell script is within quotes?

2 Answers 2

1 Comment

1 Comment

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Related