Question

I have a configuraton file that I am editing and on the first pass the is correctly changed but on the next two lines sed returns the lines blank.

The lines to be edited are

word.word.word.database=dbase
word.word.word.username=someone
word.word.word.password=someone

The sed commands I am using are

cat config.file | \sed -e "s/database/$dbname/" > config.file.1

cat config.file.1 | \sed -e "s/username/$dbuser/" > config.file.2

cat config.file.2 | \sed -e "s/database/$password/" > config.file.3

 cp config.file.3 config.file

The end result is

word.word.word.database=dbname
word.word.word.username=
word.word.word.password=

Can’t figure out what is going wrong with this. Any help would be great.

Thanks!

Answer 1

$dbname , $dbuser and $password are begin treated like shell variables, hence the leading dollar signs. If you’re trying to incorporate shell vars, try:

 sed -i -e "s/database/$dbname/" -e "s/username/$dbuser/" -e "s/password/$password/" config.file

Notice that I’ve added the -i flag to the above command. It enables in-place editing using GNU sed. Other types of sed require an extension to be set, like: -i.bak and this creates a back up file; in your case this would be: config.bak.

If you’re just looking to get the full list of results, either drop the dollarsigns or use single quotes. For example:

sed -i -e "s/database/dbname/" -e "s/username/dbuser/" -e "s/password/password/" config.file

or

sed -i -e 's/database/$dbname/' -e 's/username/$dbuser/' -e 's/password/$password/' config.file

EDIT1:

If I’ve completely mis-understood your question, try this:

sed -i -e "s/\(.*database=\).*/\1dbname/" -e "s/\(.*username=\).*/\1dbuser/" -e "s/\(.*password=\).*/\1password/" config.file

Results:

word.word.word.database=dbname
word.word.word.username=dbuser
word.word.word.password=password

EDIT2:

If you have shell vars labelled $dbname , $dbuser and $password:

sed -i -e "s/\(.*database=\).*/\1$dbname/" -e "s/\(.*username=\).*/\1$dbuser/" -e "s/\(.*password=\).*/\1$password/" config.file