CODEWITHSUNDEEP
bashsedescapingspecial-charactersdouble-quotes
fvcpinheiro
fvcpinheiro

Reputation: 49

Getting bad flag in substitute command '/' using sed replacement with custom string

I'm using macOS Sierra, and I'm and trying to manipulate a value of a key from a config file.

In order to achieve that I'm using (which works fine for simple values):

sed -i .bak "/^$KEY/s/\(.[^=]*\)\([ \t]*=[ \t]*\)\(.[^=]*\)/\1\2$VALUE/" $CONFIG_FILE

Unfortunately, my string $VALUE is quite complex with many special characters, giving me the error:

bad flag in substitute command: '/'

My $VALUE is being declared as:

VALUE='<Request xmlns="urn:oasis:names:tc:xacml:3.0:core:schema:wd-17" ReturnPolicyIdList="false" CombinedDecision="false"> <Attributes Category="urn:oasis:names:tc:xacml:3.0:attribute-category:resource"> <Attribute IncludeInResult="false" AttributeId="urn:oasis:names:tc:xacml:1.0:resource:resource-id"> <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">test </AttributeValue> </Attribute> </Attributes> <Attributes Category="urn:oasis:names:tc:xacml:3.0:attribute-category:action"> <Attribute IncludeInResult="false" AttributeId="urn:oasis:names:tc:xacml:1.0:action:action-id"> <AttributeValue DataType="http://www.w3.org/2001/XMLSchema#string">testing something</AttributeValue> </Attribute> </Attributes> </Request>'

Since I have double quotes being part of the value of $VALUE, I can't use double quotes instead of single quote when declaring it... Any ideas to workaround this?

Upvotes: 2

Views: 1118

Answers (1)

Jean-Fran&#231;ois Fabre
Jean-Fran&#231;ois Fabre

Reputation: 140297

The problem is that $VALUE contains slashes which should be escaped because it conflicts with the separator for the substiture command

That's not convenient because if it changes, you have to escape them again. That's a solution, nevertheless.

Another simpler solution is to use an alternate separating character for s command which isn't in the $VALUE string, like % for instance (% has less chance to be in such a string, otherwise | can also be used).

sed -i .bak "/^$KEY/s%\(.[^=]*\)\([ \t]*=[ \t]*\)\(.[^=]*\)%\1\2$VALUE%" $CONFIG_FILE

or with pipe:

sed -i .bak "/^$KEY/s|\(.[^=]*\)\([ \t]*=[ \t]*\)\(.[^=]*\)|\1\2$VALUE|" $CONFIG_FILE

Upvotes: 1

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