Unix: Automate replacing specific words in all the files

 

The script mentioned below is a shell script intended to automate the process of modifying control files and loading data into an Oracle database using SQL*Loader. Let's break down the script step by step:

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Script Explanation

1. Korn Shell Line:

    #!/bin/ksh

    - Specifies that the script should be executed using the Korn shell (`ksh`).

2. List and Process Control Files:

    ```bash

    ls -ltr *.ctl | awk -F" " '{print $9}'|awk -F"." '{print $1}' >> load_files

    ```

    - `ls -ltr *.ctl`: Lists all `.ctl` files (control files used by SQL*Loader) in the current directory, sorted by modification time.

    - `awk -F" " '{print $9}'`: Uses `awk` to extract the ninth field (the filename), assuming fields are separated by spaces.

    - `awk -F"." '{print $1}'`: Further processes each line to extract the filename without the `.ctl` extension.

    - `>> load_files`: Appends the filenames to a file named `load_files`.

3. Read Each Filename and Process:

    ```bash

    while read a 

    do 

    ...

    done < load_files

    ```

    - Reads each line from the `load_files` file and processes it in the loop.

4. Define Filenames:

    b=$a."ctl"
    c=$a"1"."ctl"

    - Constructs the original control filename (`b`) and a new filename (`c`) by appending `1` before the `.ctl` extension.

5. Modify and Create New Control File:

    sed 's/C:\\Users\\Documents\\Projects\\DB_DUMP\\Pipeline_DB\\//g' $b >> $c

    - Uses `sed` to remove a specific path from the content of the original control file (`b`) and writes the modified content into a new control file (`c`).

6. Print SQL*Loader Command:

    printf "sqlldr integrate/password control=$c \n"

    - Prints the SQL*Loader command that will be executed, useful for debugging or logging.

7. Execute SQL*Loader:

    sqlldr integrate/password@PINDB control=$c;

    - Executes SQL*Loader using the newly created control file (`c`). Assumes `integrate` as the username, `password` as the password, and `PINDB` as the database SID or service name.

8. Print Newlines for Formatting:

    printf "\n \n\n \n"

    - Prints a series of newline characters for better readability in the output.

Summary

The script automates the process of:

- Finding control files in the current directory.

- Creating modified versions of these files by removing a hardcoded file path.

- Loading data into an Oracle database using the modified control files with SQL*Loader.

This script is particularly useful when you need to repeatedly load data from multiple control files into a database, but first need to adjust the file paths within those control files. Remember to replace `integrate/password@PINDB` with your actual database credentials and connection string.

#!/bin/ksh 
ls -ltr *.ctl | awk -F" " '{print $9}'|awk -F"." '{print $1}' >> load_files 
while read a 
do 
b=$a."ctl" 
c=$a"1"."ctl" 
sed 's/C:\\Users\\mmgude\\Documents\\Projects\\DB_DUMP\\Pipeline_DB\\//g' $b >> $c 
printf "sqlldr integrate/password control=$c \n" 
sqlldr integrate/password@PINDB control=$c; 
printf "\n \n\n \n" 
done < load_files