Do you mean by regular unix-style write permissions, or the ext2 attributes?
For normal permissions, you can use your file manager, like konqueror, nautilus and so on - just right click on the file/dir and go to properties and there is usually something in there about permissions.
From the terminal you can also use the ls -ld /path/to/your/dir
command to view the permissions (the first column of output); and change the permissions using the chmod
command (which is a contraction of "change mode"). See the ls and chmod manual pages for more detailed descriptions of what they do. The command to add write permissions to your directory is:
chmod u+w /path/to/your/dir
This will add the "user is able to write" flag. Note that to modify the permissions of a a file or directory, you must have read write and execute permissions to the parent directory in which the file/directory exists.
If you mean not the unix-style permissions, but ext2 attributes, you can view existing attributes with the lsattr
command, and change them with the chattr
command. The attribute which sometimes makes files un-writable is the "i" flag - immutable. For example:
lsattr -d /path/to/your/dir
chattr -i /path/to/your/dir # to remove the immutable flag.
See the lsattr and chattr manual pages for more information.
I think only root can change attributes. I haven't had much exposure to them, and as far as I know they are not very widely used.