The umask command
The umask command shows and sets the default permissions:
The umask value is just that, a mask. It masks out the permissions you don’t want to give.The umask value is subtracted from the full permission set for an object. The full permission for a file is mode 666 (read/write permission for all), but for a directory it’s 777 (read/write/execute permission for all).
Thus, in the example, the file starts out with permissions 666, and the umask of 022 is applied, leaving a file permission of 644. The umask value is normally set in the /etc/profile startup file.
Tags: command, umask
The pam_time module is used as an account module-type. The pam_time module does not accept arguments. It instead uses the /etc/security/time.conf file to get information related to login time and location restrictions. There are two important points concerning the /etc/security/time.conf.
The /etc/security/time.conf file restricts access by time and location when used with pam_time.
Each line in /etc/security/time.conf file is called a rule.
Each rule uses the following syntax:
services;ttys;users;times
Tags: module, pam_time
Parallels Pro Control Panel for Linux on fresh install of CentOS 5.3 / RHEL 5.3
Prior to installation Parallels Control Panel for Linux on the mentioned operations system please check if the system has rpm user and rpm usergroup:
You need to create this user and appropriate usergroup. To do so please follow next steps:
Log as root to your PPCPL box
Type the following commands:
/usr/sbin/groupadd -g 37 rpm > /dev/null 2>&1
/usr/sbin/useradd -r -d /var/lib/rpm -u 37 -g 37 rpm -s /sbin/nologin > /dev/null 2>&1
After adding the rpm user and rpm usergroup you can proceed with the Parallels Pro Control Panel installation.
Reference : http://parallels.com/
Tags: CentOS 5.3, Control, fresh, install, linux, Panel, Parallels, RHEL 5.3
/etc/skel directory
The system will copy the contents of the /etc/skel directory to the user’s HOME directory.
The useradd command allows an administrator to create a default HOME directory configuration, then uses that as a template to create the new user’s HOME directory. This allows you to place default files for the system in every new user’s HOME directory automatically. On my Linux system, the /etc/skel directory has the following files.
root@dell:/etc/skel# ls -ld *
drwxr-xr-x 2 buddy buddy 4096 Oct 11 2008 Desktop
drwxr-xr-x 2 buddy buddy 4096 Mar 4 2009 Documents
drwxr-xr-x 2 buddy buddy 4096 Mar 4 2009 Download
drwxr-xr-x 2 buddy buddy 4096 Mar 4 2009 Music
drwxr-xr-x 2 buddy buddy 4096 Mar 4 2009 Pictures
drwxr-xr-x 2 buddy buddy 4096 Mar 4 2009 Public
drwxr-xr-x 2 buddy buddy 4096 Mar 4 2009 Templates
drwxr-xr-x 2 buddy buddy 4096 Mar 4 2009 Videos
Tags: /etc/skel, directory
System Default Values for useradd
The primary tool used to add new users to your Linux system is useradd. This command pro-
vides an easy way to create a new user account and set up the user’s HOME directory structure all at once. The useradd command uses a combination of system default values and command line parameters to define a user account.
To see the system default values used on your Linux distribution, enter the useradd command with the -D parameter.
root@dell:~# /usr/sbin/useradd -D
GROUP=100
HOME=/home
INACTIVE=-1
EXPIRE=
SHELL=/bin/sh
SKEL=/etc/skel
CREATE_MAIL_SPOOL=no
The -D parameter shows what defaults the useradd command uses.
Tags: Default, System, useradd, values
