Customizing report output in AWK

In AWK, you can customize report output by using a combination of built-in variables, functions, and control structures. Here are some commonly used techniques for customizing report output in AWK:

- **Built-in variables:** AWK provides several built-in variables that you can use to customize report output. Here are some commonly used built-in variables:

  - `ORS`: The output record separator. By default, this is a newline character, but you can change it to any string you like using the `-v` option. For example, `awk -v ORS="\t" '...'` sets the output record separator to a tab character.
  - `OFS`: The output field separator. By default, this is a space character, but you can change it to any string you like using the `-v` option. For example, `awk -v OFS="," '...'` sets the output field separator to a comma.
  - `RS`: The input record separator. By default, this is a newline character, but you can change it to any string you like using the `-v` option. For example, `awk -v RS="|" '...'` sets the input record separator to a pipe character.

- **Functions:** You can use built-in or user-defined functions to implement custom report generation logic. Here is an example of using a user-defined function in AWK to customize report output:

  

`
  # Generate a report of the totalnumber of characters in each input file, with a custom header and footer
  BEGIN {
    printf "Report of Total Characters in Input Files\n"
    printf "==========================================\n"
    printf "%-20s %s\n", "File Name", "Character Count"
    printf "%-20s %s\n", "---------", "---------------"
  }
  {
    count += length($0)
  }
  END {
    printf "%-20s %d\n", "Total", count
    printf "==========================================\n"
  }
  

“

In this example, we use the user-defined function `print_line` to print a line of output in a formatted manner. We use the `BEGIN` block to print a custom header for the report, and the `END` block to print a custom footer. We use the `printf` statement to format the output and the `length` function to count the number of characters in each line. We also use the `\n` escape sequence to print a newline character at the end of each line.

– **Control structures:** You can use control structures (`if`, `else`, `while`, etc.) to implement conditional logic and looping in your report generation code. Here is an example of using an `if` statement in AWK to customize report output:

# Generate a report of all employees, with a custom message for managers
BEGIN {
FS = “,”
}
{
printf “%-20s %-20s %-10s\n”, “First Name”, “Last Name”, “Role”
printf “%-20s %-20s %-10s\n”, “———-“, “———“, “—-”
}
{
if ($4 == “Manager”) {
printf “%-20s %-20s %-10s (This is a manager)\n”, $1, $2, $4
} else {
printf “%-20s %-20s %-10s\n”, $1, $2, $4
}
}

In this example, we use the `if` statement to check if an employee’s role is “Manager”. If so, we print a custom message indicating that this is a manager. If not, we print the employee’s first name (`$1`), last name (`$2`), and role (`$4`) in a formatted manner.

These are just a few examples of the techniques that you can use in AWK to customize report output. You can combine these techniques with other AWK features to implement complex reporting and analysis tasks. Remember that AWK is a powerful tool for text processing and manipulation, and can be used to customize report output in a wide range of formats.