Find and Replace in Vi editor

Syntax for Text Substitution inside the vi editor is,

:[range]s[ubstitute]/{pattern}/{string}/[Flags] [count]

Following are the possible Flags

[g] -> replace all occurances in the line.
[c] -> Confirm each substitution
[i] -> make case insensitive

Case 1: Replace a text with another in the whole file

:%s/oldText/newText/g

where %s indicates all lines in the file.

Case 2: Replace a text within a single line

:s/oldText/newText/g

No range was specified therefore it replaces text in the single line.

:s/I/oldText/newText/g

where I indicates case insensitive

Case 3: Replace a text within a range of lines

:1,10s/oldText/newText/g

replaces text between line 1 and 10

Case 4: Replace text in only the first N lines

:s/oldText/newText/g 5

replaces the text in 5 lines from the current cursor position.

Case 5: Replace the whole word and not the partial word

:s/\<his\>/her/

The standard replace will make the word history with herstory. Enclose the word with < and > to ensure the search is for the whole word and not for partial one.

Case 6: Interactive Find and Replace

:%s/oldText/newText/gc

This will prompt for confirmation.

replace with newText (y/n/a/q/l/^E/^Y)?

y -> replace the highlighted word. After replace moves to the next word.
n -> does not replace the highlighted word. Moves to the next word.
a -> replace all the highlighted words.
l -> replaces the current highlighted word and terminates the find and replace.


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DataGuard Process Architecture

As shown in the figure below, the Data Guard operations involve many processes.



Let us see what each process is used for one by one,

In the Primary Site,

LGWR or ARCH: The redolog/archivelog from the primary database is shipped to the standby database site through LGWR/ARCH processes.

FAL (Fetch Archive Log): When there is a communication loss between primary and standby (for example, network failure), the log shipping is affected and there may be gaps. When the communication is established again the FAL processes enable the automatic gap resolution and resynchronization process.

In the Standby Site,

RFS (Remote File Server): The RFS process receives the redo records from the Primary site.

MRP (Managed Recovery Process): MRP applies the redo records to the Physical Standby databases.

LSP (Logical Standby Process): The LSP process translates the redo records in to SQL and fires the SQL to the logical standby databases.

If Data Guard Broker is enabled then DMON Process is enabled on both the primary and standby sites.

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