uCertify Articles » Junior Level Linux Professional (LPIC-1) http://www.ucertify.com/article Just another WordPress weblog Wed, 04 Nov 2009 00:00:00 +0000 http://wordpress.org/?v=2.8.4 en hourly 1 What is chage command? http://www.ucertify.com/article/what-is-chage-command-2.html http://www.ucertify.com/article/what-is-chage-command-2.html#comments Thu, 10 Sep 2009 00:00:00 +0000 uCertify 2201121

The chage command is used for changing user password expiry information.

Syntax:

chage [-m mindays] [-M maxdays] [-d lastday] [-E expireday] [-I inactive] [-W warndays] [-l] user

The functions of the switches are as follows:

Switch Meaning
-m Minimum number of days between each successive password change.
-M Maximum number of days during which a password remains valid.
-d Number of days since January 1st, 1970 when a password was last changed.
-E The date on which the user account will no longer be accessible.
-I Number of days since the expiry of a user password when an account is locked.
-W Number of days of warning before a password change is required.
-l Used by a non-administrative user to check his account/password expiry status.
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Set user ID (SUID) and Set group ID (SGID) are used to set a file to run as something other than the standard. Normally, when a file is executed, it runs as the user who invokes it. Setting a file to SUID or SGID simply requires adding an extra digit to the permissions. Technically, if no digit is used, it assumes a leading 0.

Digits SID Settings
0 Standard: File runs as the user who invokes it.
2 SGID: File runs as a member of its group.
4 SUID: File runs as its owner.
6 Both SUID and SGID.
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The CRON daemon executes the CRON jobs at a specified schedule. It constantly checks the queue for the jobs that need to run. All CRON jobs are stored in the /etc/crontab file. For recurring automated jobs, CRON is considered to be the best tool.

Share/Bookmark]]> http://www.ucertify.com/article/what-is-cron-daemon-2.html/feed 0 What is a regular expression? http://www.ucertify.com/article/what-is-a-regular-expression_5607322.html http://www.ucertify.com/article/what-is-a-regular-expression_5607322.html#comments Mon, 20 Jul 2009 00:00:00 +0000 uCertify 5607322 Download free practice test for LPI Junior Level Linux Professional (LPIC-1) exam. Author : Yong Mook Kim Download free practice test for LPI Linux Professional exam. Website : http://www.mkyong.com Pass LPI ucp - UCP -->

A regular expression is a string that describes or matches a set of strings, according to certain syntax rules. Regular expressions are used by many text editors and utilities to search and manipulate bodies of text based on certain patterns. Many programming languages support regular expressions for string manipulation.

Download practice question and study guide for 117-101 for exam. Pass Junior Level Linux Professional-II in first attampt. Share/Bookmark]]> http://www.ucertify.com/article/what-is-a-regular-expression_5607322.html/feed 0 What is chage command? http://www.ucertify.com/article/what-is-chage-command.html http://www.ucertify.com/article/what-is-chage-command.html#comments Fri, 17 Jul 2009 00:00:00 +0000 uCertify 2201121

The chage command is used for changing user password expiry information.

Syntax:

chage [-m mindays] [-M maxdays] [-d lastday] [-E expireday] [-I inactive] [-W warndays] [-l] user

The functions of the switches are as follows:

Switch Meaning
-m Minimum number of days between each successive password change.
-M Maximum number of days during which a password remains valid.
-d Number of days since January 1st, 1970 when a password was last changed.
-E The date on which the user account will no longer be accessible.
-I Number of days since the expiry of a user password when an account is locked.
-W Number of days of warning before a password change is required.
-l Used by a non-administrative user to check his account/password expiry status.
Share/Bookmark]]> http://www.ucertify.com/article/what-is-chage-command.html/feed 0 What is sticky bit? http://www.ucertify.com/article/what-is-sticky-bit.html http://www.ucertify.com/article/what-is-sticky-bit.html#comments Thu, 09 Jul 2009 00:00:00 +0000 uCertify 1401441

The sticky bit is a part of a permission set applied to files or folders. The sticky bit prevents others from deleting files from a folder. When the sticky bit is set on a directory, only the owner or root can unlink (delete) or rename the files in that directory. Without the sticky bit, anyone who is able to write to the directory can delete or rename the files.

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Set user ID (SUID) and Set group ID (SGID) are used to set a file to run as something other than the standard. Normally, when a file is executed, it runs as the user who invokes it. Setting a file to SUID or SGID simply requires adding an extra digit to the permissions. Technically, if no digit is used, it assumes a leading 0.

Digits SID Settings
0 Standard: File runs as the user who invokes it.
2 SGID: File runs as a member of its group.
4 SUID: File runs as its owner.
6 Both SUID and SGID.
Share/Bookmark]]> http://www.ucertify.com/article/what-are-suid-and-sgid.html/feed 0 What are the capabilities of a SELECT statement? http://www.ucertify.com/article/what-are-the-capabilities-of-a-select-statement.html http://www.ucertify.com/article/what-are-the-capabilities-of-a-select-statement.html#comments Thu, 02 Jul 2009 00:00:00 +0000 uCertify 1801070

Following are the capabilities of a SELECT statement:

  • Projection: This capability is used to choose the columns of a table, which a user wants a SELECT statement to return.

  • Selection: This capability is used to choose the rows of a table, which a user wants a SELECT statement to return.

  • Joining: This capability is used to retrieve data from multiple tables by creating a link between them.
    • Share/Bookmark]]>     http://www.ucertify.com/article/what-are-the-capabilities-of-a-select-statement.html/feed 0     What is superblock? http://www.ucertify.com/article/what-is-superblock.html http://www.ucertify.com/article/what-is-superblock.html#comments Tue, 30 Jun 2009 00:00:00 +0000 uCertify 1401192

    The superblock is an area in a storage device of a Linux computer, which stores various bits of information about a file system, such as a pointer to the free blocks structure, the number of free inodes, etc. In case the superblock is damaged and cannot be read, an error message is generated by the system. In this case, the E2FSCK utility is used to troubleshoot the issue by passing the superblock parameter manually.

    Share/Bookmark]]>     http://www.ucertify.com/article/what-is-superblock.html/feed 0     What is IFCONFIG command? http://www.ucertify.com/article/what-is-ifconfig-command.html http://www.ucertify.com/article/what-is-ifconfig-command.html#comments Mon, 29 Jun 2009 00:00:00 +0000 uCertify 1401168

    IFCONFIG is a command-line tool, which is used for network interface management. Following are some of the options used with the command:

    • up: This option is used to activate the specified interface.

    • down: This option is used to deactivate the specified interface.

    • lo: This option is used to view the loopback interface.

    The IFCONFIG command is also used to configure an interface.

    Syntax:

    IFCONFIG interface options

    For example, to configure a Linux computer’s first network interface with an IP address 200.200.200.123 and subnet mask 255.255.255.0, the following command is used:

    IFCONFIG eth0 200.200.200.123 netmask 255.255.255.0

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