BTW this assumes that the config file is simple and there is no order needed between the various lines.
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Shell Scripting to read/write values from virables in config files
Hello,
I'm new to shell scripting, but so far I love it :-)
here is my question
I want to find a way to read (or/and change if needed) a value from a config files (mostly will be located in /etc)
is there any easy way to do it?
basically it will be like 2 functions one to read the value to a variable in my script and the other is to change the value to any thing I give!
cheers,
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Answers
@noci, nice and simple. Can I make one suggestion? In your grep, always ensure that you tie it to the first character position with ^, otherwise you may get more than 1 line returned:
$ echo cfgvar=TEST >> greg
$ grep 'cfgvar=' greg
cfgvar=TEST
$ echo new_cfgvar=NEW_TEST >> greg
$ grep 'cfgvar=' greg
cfgvar=TEST
new_cfgvar=
$ grep '^cfgvar=' greg
cfgvar=TEST
$ grep 'cfgvar=' greg
cfgvar=TEST
$ echo new_cfgvar=NEW_TEST >> greg
$ grep 'cfgvar=' greg
cfgvar=TEST
new_cfgvar=
$ grep '^cfgvar=' greg
cfgvar=TEST
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by: nociPosted on 2009-08-14 at 07:56:15ID: 25098681
writing to a file:
The cfgvar is the name of the config variable.
$VAL is the value you want to give it.
adding:
echo cfgvar=$VAL >>/etc/configfile
deleting a line
grep -v 'cfgvar=' /etc/configfile >/etc/configfile.1 ; mv /etc/configfile.1 /etc/configfile
updating can also be done by: (by first removing a line from the file and then add it back with a new one
(grep -v 'cfgvar=' /etc/configfile ; echo cfgvar=$VAL ) >/etc/configfile.1 ; mv /etc/configfile.1 /etc/configfile
reading can be done through
VAL=$( grep cfgvar= /etc/configfile | sed -e 's/cfgvar=//' )
Updating can also be done through sed.