Find out where configuration changes are stored

From LinuxIntro
Jump to: navigation, search

You may ask yourself "where are my configuration settings stored". The reason why you want to know is may be that you are the administrator and want your users to have some specific options set. This article introduces a methodology how to identify the places of configuration setting on the example of the program konsole.

Whenever I set up a computer, I start konsole and change its settings. I choose Settings -> Configure Current Profile -> Tabs -> "Show 'New Tab' and 'Close Tab' buttons in tab bar". Today I wanted to write a script to do this configuration change for me. The most important question is - where is this setting being saved?

The strace approach

I could find this out using the command

strace -ffe open konsole

strace is a cool command that shows you every syscall invoked by a program (in the above case konsole). When called with the -e open argument, it will only show the open syscalls. This gives you a powerful tool into your hands: A monitor which files are read and/or modified by a program. The output will read like this:

[pid 29951] open("/etc/localtime", O_RDONLY) = 3
[pid 29951] open("/etc/kde4rc", O_RDONLY|O_CLOEXEC) = 3
[pid 29951] open("/root/.kde4/share/config/kdeglobals", O_RDONLY|O_CLOEXEC) = 3

The -ff argument is needed so strace still follows spawning processes; for more information, read strace's man page.

So I did open a console, entered

strace -ffe open konsole

A konsole window popped up and I chose Settings -> Configure Current Profile -> Tabs -> "Show 'New Tab' and 'Close Tab' buttons in tab bar". When I clicked on "Apply", I found a line saying

[pid 29951] open("/root/.kde4/share/apps/konsole/Shell.profile", O_RDONLY|O_CLOEXEC) = 16

And I could verify my changes go to /root/.kde4/share/apps/konsole/Shell.profile:

# cat /root/.kde4/share/apps/konsole/Shell.profile 
[...]
ShowNewAndCloseTabButtons=false
[...]

The find approach

I started konsole, chose Settings -> Configure Current Profile -> Tabs -> "Show 'New Tab' and 'Close Tab' buttons in tab bar" -> Apply. Then I typed a command to find all files newer than 0.01 days:

cd
find . -ctime -0.01

And I found the output

./.kde4/share/apps/konsole/Shell.profile

This means my configuration changes were saved in the file .kde4/share/apps/konsole/Shell.profile.