CODEWITHSUNDEEP
sedescapingdouble-quotes
GenXRoad
GenXRoad

Reputation: 1

sed and double quotes

I have a problem with a script, if the file test.cfg doesn't exist then the correct Password will be written in the file test.cfg, but if the test.cfg exists then the Password won't get changed.

Here is my script test.sh -password mysecret

#!/bin/bash
while test $# -gt 0; do
    case "$1" in
        "-password" )
        password="$2"
        shift
    ;;
    esac
shift
done

grep "password = " test.cfg &>/dev/null
if [[ $? -eq 0 ]]; then # Vorhanden!
    sed -i test.cfg -e "s/^\(password = \).\"*$/\1${password}\";/"
else # Nicht vorhanden!
    echo "password = \"${password}\";" >> test.cfg
fi

When the test.cfg does not exist it will be created with Content

password = "mysecret";

but now the line exists, then the password won't get changed to test.sh -password mynewsecret

It's only get changed to:

password = mynewsecret;

Upvotes: 0

Views: 147

Answers (2)

Jonathan Leffler
Jonathan Leffler

Reputation: 754620

The problem is that your replacement string doesn't include the double quotes that you remove, and your code doesn't match what you expect either. Use this — it moves the first \" to the correct place.

sed -i -e "s/^\(password = \).*$/\1\"${password}\";/" test.cfg

As an aside, you must be using GNU sed. Mac OS X sed complains sed: -i may not be used with stdin because it expects an argument to -i, so it treats test.cfg as the suffix to be added to the backup file (and therefore there is no file name argument, so it is reading from standard input). I still think it is best to put option arguments before non-option arguments, even though GNU getopt(1) (or getopt_long(1)) supports interleaving option and non-option arguments. I've reordered the command line appropriately. It still won't work on Mac OS X; the suffix is not optional with the -i there.

Upvotes: 0

choroba
choroba

Reputation: 242038

\"* means *double quote zero or more times. You need a bit different regular expression:

sed -e "s/^\(password = \)\".*\"$/\1\"$password\";/"

Note that case is suitable if there is more then one possibility, here if would be more suitable:

while (( $# )) ; do
    if [[ $1 == '-password' ]] ; then
        password=$2
        shift
    fi
    shift    # What does this do, anyway?
done

if grep -q 'password = ' test.cfg ; then
    sed -i~ -e "s/^\(password = \)\".*\"$/\1\"$password\";/" test.cfg
else
    echo 'password = "'"$password"'";' >> test.cfg
fi

Upvotes: 1

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