As subtle as a flying brick.

Be careful what you show the world.
You never know when the wolf is watching.

― Jennifer Donnelly, Revolution

Latest

You should date a girl who reads.

You should date a girl who reads.

Date a girl who reads. Date a girl who spends her money on books instead of clothes, who has problems with closet space because she has too many books. Date a girl who has a list of books she wants to read, who has had a library card since she was twelve.

Find a girl who reads. You’ll know that she does because she will always have an unread book in her bag. She’s the one lovingly looking over the shelves in the bookstore, the one who quietly cries out when she has found the book she wants. You see that weird chick sniffing the pages of an old book in a secondhand book shop? That’s the reader. They can never resist smelling the pages, especially when they are yellow and worn.

She’s the girl reading while waiting in that coffee shop down the street. If you take a peek at her mug, the non-dairy creamer is floating on top because she’s kind of engrossed already. Lost in a world of the author’s making. Sit down. She might give you a glare, as most girls who read do not like to be interrupted. Ask her if she likes the book.

Buy her another cup of coffee.

Let her know what you really think of Murakami. See if she got through the first chapter of Fellowship. Understand that if she says she understood James Joyce’s Ulysses she’s just saying that to sound intelligent. Ask her if she loves Alice or she would like to be Alice.

It’s easy to date a girl who reads. Give her books for her birthday, for Christmas, for anniversaries. Give her the gift of words, in poetry and in song. Give her Neruda, Pound, Sexton, Cummings. Let her know that you understand that words are love. Understand that she knows the difference between books and reality but by god, she’s going to try to make her life a little like her favorite book. It will never be your fault if she does.

She has to give it a shot somehow.

Lie to her. If she understands syntax, she will understand your need to lie. Behind words are other things: motivation, value, nuance, dialogue. It will not be the end of the world.

Fail her. Because a girl who reads knows that failure always leads up to the climax. Because girls who read understand that all things must come to end, but that you can always write a sequel. That you can begin again and again and still be the hero. That life is meant to have a villain or two.

Why be frightened of everything that you are not? Girls who read understand that people, like characters, develop. Except in the Twilight series.

If you find a girl who reads, keep her close. When you find her up at 2 AM clutching a book to her chest and weeping, make her a cup of tea and hold her. You may lose her for a couple of hours but she will always come back to you. She’ll talk as if the characters in the book are real, because for a while, they always are.

You will propose on a hot air balloon. Or during a rock concert. Or very casually next time she’s sick. Over Skype.

You will smile so hard you will wonder why your heart hasn’t burst and bled out all over your chest yet. You will write the story of your lives, have kids with strange names and even stranger tastes. She will introduce your children to the Cat in the Hat and Aslan, maybe in the same day. You will walk the winters of your old age together and she will recite Keats under her breath while you shake the snow off your boots.

Date a girl who reads because you deserve it. You deserve a girl who can give you the most colorful life imaginable. If you can only give her monotony, and stale hours and half-baked proposals, then you’re better off alone. If you want the world and the worlds beyond it, date a girl who reads.

Or better yet, date a girl who writes.

Rosemarie Urquico

How to clean up dated folders

Suppose you have a backup directory with backup snapshots named by timestamp:

$ ls
2013-05-03-103022
2013-05-04-103033
2013-05-05-103023
2013-05-06-103040
2013-05-07-103022

You want to remove snapshots older than 3 days. The one-liner does it:

$ date
Tue May  7 13:50:57 KST 2013
$ ls | grep '....-..-..-......' | sort | xargs -I {} bash -c "[[ x{} < x$(date -d '3 days ago' +%Y-%m-%d-%H%M%S) ]] && rm -rfv {}"
removed directory: `2013-05-03-103022'
removed directory: `2013-05-04-103033'

 

Aside

Linux turn OFF password expiration / aging

/etc/shadow stores actual password in encrypted format for user’s account with additional properties related to user password.

The password expiration information for a user is contained in the last 6 fields. Password expiration for a select user can be disabled by editing the /etc/shadow file

However I recommend using chage command. The chage command changes the number of days between password changes and the date of the last password change.

This information is used by the system to determine when a user must change his/her password.

To list current aging type chage command as follows:

# chage -l vivek

Output:

Last password change                                    : August 23, 2013
Password expires                                        : never
Password inactive                                       : never
Account expires                                         : never
Minimum number of days between password change          : 0
Maximum number of days between password change          : 99999
Number of days of warning before password expires       : 7

To disable password aging / expiration for user foo, type command as follows and set:

Minimum Password Age to 0
Maximum Password Age to 99999
Password Inactive to -1
Account Expiration Date to -1

Interactive mode command:

# chage username

OR

# chage -I -1 -m 0 -M 99999 -E -1 username

Understanding /etc/shadow file

Q. Can you explain /etc/shadow file used under Linux or UNIX?

A. /etc/shadow file stores actual password in encrypted format for user’s account with additional properties related to user password i.e. it stores secure user account information.

All fields are separated by a colon (:) symbol. It has one entry per line for each user listed in /etc/passwd file Generally, shadow file entry looks as follows:

shadow-file

(Fig.01: /etc/shadow file fields)

  1. User name : It is your login name
  2. Password: It your encrypted password. The password should be minimum 6-8 characters long including special characters/digits
  3. Last password change (lastchanged): Days since Jan 1, 1970 that password was last changed
  4. Minimum: The minimum number of days required between password changes i.e. the number of days left before the user is allowed to change his/her password
  5. Maximum: The maximum number of days the password is valid (after that user is forced to change his/her password)
  6. Warn : The number of days before password is to expire that user is warned that his/her password must be changed
  7. Inactive : The number of days after password expires that account is disabled
  8. Expire : days since Jan 1, 1970 that account is disabled i.e. an absolute date specifying when the login may no longer be used

The last 6 fields provides password aging and account lockout features (you need to use chage command to setup password aging). According to man page of shadow – the password field must be filled. The encrypted password consists of 13 to 24 characters from the 64 character alphabet a through z, A through Z, 0 through 9, \. and /. Optionally it can start with a “$” character. This means the encrypted password was generated using another (not DES) algorithm. For example if it starts with “$1$” it means the MD5-based algorithm was used.

Understanding /etc/passwd

Q. Can you explain /etc/passwd file format for Linux and UNIX operating systems?

A. /etc/passwd file stores essential information, which is required during login i.e. user account information. /etc/passwd is a text file, that contains a list of the system’s accounts, giving for each account some useful information like user ID, group ID, home directory, shell, etc. It should have general read permission as many utilities, like ls use it to map user IDs to user names, but write access only for the superuser (root).

Understanding fields in /etc/passwd

The /etc/passwd contains one entry per line for each user (or user account) of the system. All fields are separated by a colon (:) symbol. Total seven fields as follows.

Generally, passwd file entry looks as follows (click to enlarge image):

passwd-file

Fig.01: /etc/passwd file format

  1. Username: It is used when user logs in. It should be between 1 and 32 characters in length.
  2. Password: An x character indicates that encrypted password is stored in /etc/shadow file.
  3. User ID (UID): Each user must be assigned a user ID (UID). UID 0 (zero) is reserved for root and UIDs 1-99 are reserved for other predefined accounts. Further UID 100-999 are reserved by system for administrative and system accounts/groups.
  4. Group ID (GID): The primary group ID (stored in /etc/group file)
  5. User ID Info: The comment field. It allow you to add extra information about the users such as user’s full name, phone number etc. This field use by finger command.
  6. Home directory: The absolute path to the directory the user will be in when they log in. If this directory does not exists then users directory becomes /
  7. Command/shell: The absolute path of a command or shell (/bin/bash). Typically, this is a shell. Please note that it does not have to be a shell.

Task: See User List

/etc/passwd is only used for local users only. To see list of all users, enter:
$ cat /etc/passwd
To search for a username called tom, enter:
$ grep tom /etc/passwd

/etc/passwd file permission

The permission on the /etc/passwd file should be read only to users (-rw-r--r--) and the owner must be root:
$ ls -l /etc/passwd
Output:

-rw-r--r-- 1 root root 2659 Sep 17 01:46 /etc/passwd

Reading /etc/passwd file

You can read /etc/passwd file using the while loop and IFS separator as follows:

#!/bin/bash
# seven fields from /etc/passwd stored in $f1,f2...,$f7
# 
while IFS=: read -r f1 f2 f3 f4 f5 f6 f7
do
 echo "User $f1 use $f7 shell and stores files in $f6 directory."
done < /etc/passwd

Your password is stored in /etc/shadow file

Your encrypted password is not stored in /etc/passwd file. It is stored in /etc/shadow file. In the good old days there was no great problem with this general read permission. Everybody could read the encrypted passwords, but the hardware was too slow to crack a well-chosen password, and moreover, the basic assumption used to be that of a friendly user-community.

Almost, all modern Linux / UNIX line operating systems use some sort of the shadow password suite, where /etc/passwd has asterisks (*) instead of encrypted passwords, and the encrypted passwords are in /etc/shadow which is readable by the superuser only.

I’m not a fanboy, but aww.

it’s so much easier to say you’re anti social…

image

…or claim that you just don’t like people…

image

…or pretend that you just don’t care anymore…

image

…than to admit how lonely and damaged you truly feel.

image

Half-Life 2 For Steam on Linux

The first-person shooter Half-Life 2 released for Steam on Linux. I truly enjoyed Counter Strike, and I am going to install Half-Life 2 this weekend. From the release notes:

Half Life 2 logo

Half-Life 2, Half-Life 2: Episode 1, Half-Life 2: Episode 2 and Half-Life 2: LostCoast are now available as a Beta. This beta adds Linux support and converts the game to the new Steam Content delivery system.

Linux users can simply install the games access the beta. For Windows and OS X users right click the game in your Library, choose properties and then go to the Beta tab. Select the SteamPipe beta to start testing. Under Windows and OS X to opt out of testing simply deselect the beta option on this same page.

I think Valve has done a good job, and I’m hoping more game developers will release popular games on Linux.

 

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