Command Line Shortcuts, Cool Tricks and Tools, Reference Material

VI Cheat Sheet

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Modes

Vi has two modes insertion mode and command mode. The editor begins in command mode, where the cursor movement and text deletion and pasting occur. Insertion mode begins upon entering an insertion or change command. [ESC] returns the editor to command mode (where you can quit, for example by typing :q!). Most commands execute as soon as you type them except for “colon” commands which execute when you press the ruturn key.

Quitting

:wq Exit, saving changes
:q Exit as long as there have been no changes
ZZ Exit and save changes if any have been made
:q! Exit and ignore any changes

Inserting Text

i Insert before cursor
I Insert before line
a Append after cursor
A Append after line
o Open a new line after current line
O Open a new line before current line
r Replace one character
R Replace many characters

Motion

h Move left
j Move down
k Move up
l Move right
w Move to next word
W Move to next blank delimited word
b Move to the beginning of the word
B Move to the beginning of blank delimted word
e Move to the end of the word
E Move to the end of Blank delimited word
( Move a sentence back
) Move a sentence forward
{ Move a paragraph back
} Move a paragraph forward
0 Move to the begining of the line
$ Move to the end of the line
1G Move to the first line of the file
G Move to the last line of the file
nG Move to nth line of the file
:n Move to nth line of the file
fc Move forward to c
Fc Move back to c
H Move to top of screen
M Move to middle of screen
L Move to botton of screen
% Move to associated ( ), { }, [ ]

Deleting Text

Almost all deletion commands are performed by typing d followed by a motion. For example, dw deletes a word. A few other deletes are:
x Delete character to the right of cursor
X Delete character to the left of cursor
D Delete to the end of the line
dd Delete current line
:d Delete current line

Yanking Text

Like deletion, almost all yank commands are performed by typing y followed by a motion. For example, y$ yanks to the end of the line. Two other yank commands are:
yy Yank the current line
:y Yank the current line

Changing text

The change command is a deletion command that leaves the editor in insert mode. It is performed by typing c followed by a motion. For wxample cw changes a word. A few other change commands are:
C Change to the end of the line
cc Change the whole line

Putting text

p Put after the position or after the line
P Put before the poition or before the line

Buffers

Named buffers may be specified before any deletion, change, yank or put command. The general prefix has the form “c where c is any lowercase character. for example, “adw deletes a word into buffer a. It may thereafter be put back into text with an appropriate “ap.

Markers

Named markers may be set on any line in a file. Any lower case letter may be a marker name. Markers may also be used as limits for ranges.
mc Set marker c on this line
`c Go to beginning of marker c line.
‘c Go to first non-blank character of marker c line.

Search for strings

/string Search forward for string
?string Search back for string
n Search for next instance of string
N Search for previous instance of string

Replace

The search and replace function is accomplished with the :s command. It is commonly used in combination with ranges or the :g command (below).
:s/pattern/string/flags Replace pattern with string according to flags.
g Flag – Replace all occurences of pattern
c Flag – Confirm replaces.
& Repeat last :s command

Regular Expressions

. (dot) Any single character except newline
* zero or more occurances of any character
[…] Any single character specified in the set
[^…] Any single character not specified in the set
^ Anchor – beginning of the line
$ Anchor – end of line
\< Anchor – begining of word
\> Anchor – end of word
\(…\) Grouping – usually used to group conditions
\n Contents of nth grouping

 

[…] – Set Examples
[A-Z] The SET from Capital A to Capital Z
[a-z] The SET from lowercase a to lowercase z
[0-9] The SET from 0 to 9 (All numerals)
[./=+] The SET containing . (dot), / (slash), =, and +
[-A-F] The SET from Capital A to Capital F and the dash (dashes must be specified first)
[0-9 A-Z] The SET containing all capital letters and digits and a space
[A-Z][a-zA-Z] In the first position, the SET from Capital A to Capital Z
In the second character position, the SET containing all letters

 

Regular Expression Examples
/Hello/ Matches if the line contains the value Hello
/^TEST$/ Matches if the line contains TEST by itself
/^[a-zA-Z]/ Matches if the line starts with any letter
/^[a-z].*/ Matches if the first character of the line is a-z and there is at least one more of any character following it
/2134$/ Matches if line ends with 2134
/\(21|35\)/ Matches is the line contains 21 or 35
Note the use of ( ) with the pipe symbol to specify the ‘or’ condition
/[0-9]*/ Matches if there are zero or more numbers in the line
/^[^#]/ Matches if the first character is not a # in the line
Notes:
1. Regular expressions are case sensitive
2. Regular expressions are to be used where pattern is specified

Counts

Nearly every command may be preceded by a number that specifies how many times it is to be performed. For example, 5dw will delete 5 words and 3fe will move the cursor forward to the 3rd occurence of the letter e. Even insertions may be repeated conveniently with thismethod, say to insert the same line 100 times.

Ranges

Ranges may precede most “colon” commands and cause them to be executed on a line or lines. For example :3,7d would delete lines 3-7. Ranges are commonly combined with the :s command to perform a replacement on several lines, as with :.,$s/pattern/string/g to make a replacement from the current line to the end of the file.
:n,m Range – Lines n–m
:. Range – Current line
:$ Range – Last line
:’c Range – Marker c
:% Range – All lines in file
:g/pattern/ Range – All lines that contain pattern

Files

:w file Write to file
:r file Read file in after line
:n Go to next file
:p Go to previos file
:e file Edit file
!!program Replace line with output from program

Other

~ Toggle upp and lower case
J Join lines
. Repeat last text-changing command
u Undo last change
U Undo all changes to line

 

Special thanks to LAGMONSTER.ORG for this Cheat Sheet

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12 Reasons Why Every System Administrator Should be Lazy

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System administrators job is not visible to other IT groups or end-users. Mostly they look at administrators and wonder why sysadmins don’t seem to have any work.

If you see a sysadmin who is always running around, and trying to put down fire, and constantly dealing with production issues, you might think he is working very hard, and really doing his job. But in reality he is not really doing his job.

If you see a sysadmin (UNIX/Linux sysadmin, or DBA, or Network Administrators), who doesn’t seem to be doing much around the office that you can see, he always seem to be relaxed, and he don’t seem to have any visible work, you can be assured that he is doing his job.

The following are the 12 reasons why a lazy sysadmin is the best sysadmin.

  1. Who is the boss? The main reason why lazy sysadmin is the best sysadmin is because of his attitude. They look at the machines little differently than how other IT departments looks at them. There is a difference between developers and sysadmins. Developers thinks they are here to serve the machines by developing code. There is nothing wrong in this approach, as developers have lot of fun developing the code. But, sysadmins think other way around. They think the machines are there to serve them. All they have to do is feed the machine and keep it happy, and let the machine do all the heavy duty job, while they can relax and just be lazy. The first step in being a lazy sysadmin is a slight change in attitutde, and letting the machine know that you are the boss.
  2. Write scripts for repeated jobs. Being lazy means being smart. A smart sysadmin is a master in all scripting languages (bash, awk, sed, etc.,). Anytime he is forced to do some work, and if there is a remote possibility that the work might be needed in the future, he writes a script to complete the job. This way, in the future when he was requested to do the same job, he doesn’t have to think; he just have to execute the script, and get back to being lazy.
  3. Backup everything. Being lazy means taking backup. A lazy sysadmin knows that he has to put little work in creating a backup process, and write backup scripts for all critical systems and applications. When the disk space is not an issue, he schedules the backup job for every application, even for those that are not critical. This way, when something goes wrong, he doesn’t have to break a sweat, and just have to restore from the backup, and get back to whatever lazy stuff he was doing before. This is also the rule#1 in the three sysadmin rules that you shouldn’t break.
  4. Create a DR plan. Sysadmins doesn’t like to run around when things go wrong. When things are running smoothly, they take some time to create a DR plan. This way, when things go wrong, they can follow the DR plan and quickly get things back to normal, and get back to being lazy again.
  5. Configure highly redundant systems. Lazy sysadmins don’t like to get calls in the middle of the night because of some silly hardware failure problem. So, they make sure all the components are highly redundant. This includes both hardware and software. They have dual network card configured, they have dual power, they have dual hard drives, they have dual of everything. This way, when one component fails, the system still keeps running, and the lazy sysadmin can work on fixing the broken component after he wakes-up in the morning.
  6. Head room for unexpected growth. Lazy sysadmin never allows his system to run in full capacity. He always has enough head room for unexpected growth. He make sure the system has plenty of CPU, RAM and hard disk available. When the business unit decides to dump tons of data over night, he doesn’t have to think about how to handle that unexpected growth.
  7. Be proactive. Being lazy doesn’t mean you just sit and do nothing all the times. Being lazy means being proactive. Lazy sysadmins hate being reactive. They are always anticipating issues and anticipating growth. When they have some free time in their hand, they always work on proactive projects that helps them to avoid unexpected future issues, and to handle future growth.
  8. Loves keyboard shortcut. Lazy sysadmin knows all the keyboard shortcuts for all his favorite applications. If he spends significant time everyday on an application, the first thing he’ll do is to master the keyboard shortcut for that application. He likes to spends less them on the application to get his things done, and likes to get back to being lazy.
  9. Command line master. Every lazy sysadmin is a command line master. This applies to Linux sysadmin, dba, network administrator, etc. If you see an administrator launching a GUI, when the same task can be done from the command line, then you know he is not a lazy sysadmin. There are two reasons why lazy sysadmin loves command line. For one, he can do things quickly at the command line. For another, it makes him feel that he is the boss and not the system. When you use the command line, you are in control, you know exactly what you want to do. When you use GUI, you are at the mercy of the GUI workflow, and you are not in control.
  10. Learns from mistake. Lazy sysadmin never likes to make the same mistake twice. He hates to work on unexpected issues. But, when an unexpected issue happens, he works on fixing it, and thinks about why it happened, and he immediately puts necessary things in place so that the same issue doesn’t happen again. Working on the same problem twice is a sin according to lazy sysadmin. He likes to work on the problem only once, do things to prevent the same mistake from happening in the future, and get back to being lazy.
  11. Learn new technology. There is nothing wrong in learning a new technology to get a better job, or just to keep up with technology growth. But, lazy sysadmin doesn’t learn new technology for this reason. Instead, he learns new technology because he likes to be in control of the systems all the times. He knows he is the boss, and not the machine. So, when a new technology comes, he takes time to study them. Now he has new tools that he can use to keep the system busy, while he continue to be lazy. He learns new technology just for selfish lazy reason.
  12. Document everything. Not every lazy sysadmin does this. Only the best lazy sysadmins does this. You see, lazy sysadmin never likes to be disturbed when he is on the beach enjoying his vacation. So, what does he do? He documents everything, so that when he is not around, other junior sysadmins can do the routine job, and get things moving without disturbing his vacation. There is also another reason for the lazy sysadmin to document everything; because he forgets things. Since he is lazy, he tends to forget what he did a month ago. Since he never likes to think and research the same topic twice, he documents everything, and when he needs to do the same thing in the future, he goes back to his documentation to understand what he did earlier.

Probably you are now convinced that begin a lazy sysadmin is not that easy. It is lot of hard work. If you are not a sysadmin, you can now appreciate a lazy sysadmin when you see one. If you are sysadmin, and always running around, now you know what you need to do to be lazy.

Thanks to http://www.thegeekstuff.com for this article.

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