linux - How do I use sed to change my configuration files, with flexible keys and values? -

i want search configuration file expression: "central.database". want change setting associated "central.database" "sqltest".

the layout of config file initially:

central.database = sqlfirsttest 

this want after sed replacement:

central.database = sqltest 

i doing in bash script, suggestions, recommendations or alternative solutions welcome!

(actually both central.database , sqltest come bash variables here.)

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my current code (third attempt):

sshretvalue=$(ssh -p "35903" -i $home/sshids/idrsa-1.old ${1} <<eof         sed -i "s/^\($central_db_name\s*=\s*\).*\$/\1$central_db_value/" /home/testing.txt;         echo $? eof ) 

error message:

pseudo-terminal not allocated because stdin not terminal. sed: -e expression #1, char 58: unknown option `s' -bash: line 3: eof: command not found 

here's example expression:

sed -i 's/^\(central\.database\s*=\s*\).*$/\1sqltest/' file.cfg 

if want match stuff / in it, can use delimiter:

sed -i 's#^\(cent/ral\.data/base\s*=\s*\).*$#\1sql/test#' file.cfg 

or variable expansion:

val="sqltest" sed -i "s/^\(central\.database\s*=\s*\).*\$/\1$val/" file.cfg 

in example:

sshretvalue=`sed -i "s/^\(\1$central_db_name\s*=\s*\).*\$/\1$central_db_value/" /home/testing.txt`; 

there's \1 before $central_db_name that's invalid. also, sed doesn't print it's return value. preferred way check return values:

sed -i "s/^\($central_db_name\s*=\s*\).*\$/\1$central_db_value/" /home/testing.txt; sed_return_value=$? 

and piping ssh (not tested):

sed_return_value=$(ssh server <<eof     sed -i "s/^\($central_db_name\s*=\s*\).*\$/\1$central_db_value/" /home/testing.txt;     echo $? eof ) 

the -i replacing data in input file. otherwise sed writes stdout.

regular expressions field of own. impossible explain them in depth in stackoverflow answer, unless there specific function that's eluding you.