CODEWITHSUNDEEP
regexbusyboxash
user3155036
user3155036

Reputation: 167

How to match regexp with ash?

Following code works for bash but now i need it for busybox ash , which apparrently does not have "=~" 

keyword="^Cookie: (.*)$"
if [[ $line =~ $keyword ]]
then
bla bla
fi

Is there a suitable replacement ?

Sorry if this is SuperUser question, could not decide.

Edit: There is also no grep,sed,awk etc. I need pure ash.

Upvotes: 8

Views: 7299

Answers (4)

fabiolimace
fabiolimace

Reputation: 1227

You can use expr.

Define the function:

match() {
    local text="${1}";
    local rexp="${2}";
    # NOTE: expr regex is anchored with '^'
    expr "${text}" : "${rexp}" > /dev/null;
}

Test the function:

if match "string" "s"; then
    echo "true"
fi;

Upvotes: 0

Richard Nienaber
Richard Nienaber

Reputation: 10564

What worked for me was using Busy Box's implementations for grep and wc:

MATCHES=`echo "$BRANCH" | grep -iE '^(master|release)' | wc -l`
if [ $MATCHES -eq 0 ]; then
 echo 'Not on master or release branch'
fi

Upvotes: 4

Alex D
Alex D

Reputation: 30465

Busybox comes with an expr applet which can do regex matching (anchored to the beginning of a string). If the regex matches, its return code will be 0. Example:

 # expr "abc" : "[ab]*"
 # echo $?
 0
 # expr "abc" : "[d]*"
 # echo $?
 1

Upvotes: 3

Ciro Santilli OurBigBook.com
Ciro Santilli OurBigBook.com

Reputation: 383924

For this particular regex you might get away with a parameter expansion hack:

if [ "$line" = "Cookie: ${line#Cookie: }" ]; then
    echo a
fi

Or a pattern matching notation + case hack:

case "$line" in
    "Cookie: "*)
        echo a
    ;;
    *)
    ;;
esac

However those solutions are strictly less powerful than regexes because they have no real Kleene star * (only .*) and you should really get some more powerful tools (a real programming language like Python?) installed on that system or you will suffer.

Upvotes: 4

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