> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Bash Hybrid

> This guide demonstrates combining awk with Bash for processing text files and building a reusable salary-benchmarking tool.

This guide demonstrates how to combine the power of **awk** with **Bash** to process delimited text files. We’ll compare a pure awk script to a Bash/awk hybrid, then progressively build a reusable salary‐benchmarking tool.

***

## Why Bash-AWK Hybrids?

* Pure awk scripts are concise for text processing.
* Embedding awk inside Bash adds flexibility (variables, flags, CLI args).
* Shebangs (`#!/usr/bin/env …`) let you run scripts directly.

### Pure awk Script (`salary.awk`)

```bash theme={null}
#!/usr/bin/env awk -f
BEGIN {
    FS = "|"
}
{
    print $2, $3
}
```

### Bash Script Embedding awk (`print_names.sh`)

```bash theme={null}
#!/usr/bin/env bash
awk -F "|" '{
    print $2, $3
}'
```

You can run either script by:

```bash theme={null}
chmod +x print_names.sh
./print_names.sh < employees.txt
```

Or invoke awk directly:

```bash theme={null}
awk -f salary.awk employees.txt
```

***

## Preparing the Data Source

Our `employees.txt` file uses `|` as the field separator and contains:

| Column No | Field       | Description         |
| --------- | ----------- | ------------------- |
| 1         | Employee ID | Unique identifier   |
| 2         | First name  | Given name          |
| 3         | Last name   | Family name         |
| 4         | Department  | Department name     |
| 5         | Job title   | Position title      |
| 6         | Email       | Contact email       |
| 7         | Salary      | Annual salary (USD) |

<Frame>
  ![The image shows a text file named "employees.txt" containing a list of employees with details such as name, department, job title, email, and salary.](https://kodekloud.com/kk-media/image/upload/v1752868661/notes-assets/images/Advanced-Bash-Scripting-Bash-Hybrid/employees-list-details-text-file.jpg)
</Frame>

<Callout icon="lightbulb" color="#1CB2FE">
  Set the field separator with `-F` or `FS` to split on `|`.
</Callout>

### Salary Thresholds

| Threshold Variable | Criteria                         |
| ------------------ | -------------------------------- |
| `high_salary`      | Salary ≥ 90000 (high earners)    |
| `low_salary`       | Salary ≤ 65000 (potential bumps) |

***

## 1. Basic One-Liner

Print first name, last name, and salary for **every** employee:

```bash theme={null}
awk -F "|" '{ print $2, $3, $7 }' employees.txt
```

Output:

```text theme={null}
Kriti Shreshtha 60000
Rajasekar Vasudevan 75000
Debbie Miller 80000
Enrique Rivera 65000
Feng Lin 90000
Andy Luscomb 95000
Mark Crocker 85000
Jing Ma 100000
```

***

## 2. Filter by Salary Range

Use `-v` to pass thresholds into awk:

```bash theme={null}
awk -F "|" \
    -v high_salary=90000 \
    -v low_salary=65000 \
    '$7 >= high_salary || $7 <= low_salary {
        print $2, $3, $7
    }' employees.txt
```

This shows both high and low earners in one stream.

***

## 3. Add a Header with `BEGIN`

Introduce a one-time header via `BEGIN`:

```bash theme={null}
awk -F "|" \
    -v high_salary=90000 \
    -v low_salary=65000 \
    -v header="==== Salary Adjustments ====" \
    'BEGIN { print header }
     $7 >= high_salary || $7 <= low_salary {
         print $2, $3, $7
     }' employees.txt
```

***

## 4. Wrap into a Bash Script (`salary.sh`)

For readability and reuse, move the awk call into a Bash script:

```bash theme={null}
#!/usr/bin/env bash

awk -F "|" \
  -v high_salary=90000 \
  -v low_salary=65000 \
  -v header="==== Salary Adjustments ====" '
BEGIN {
  print header
}
$7 >= high_salary || $7 <= low_salary {
  print $2, $3, $7
}
' < employees.txt
```

Make it executable and run:

```bash theme={null}
chmod +x salary.sh
./salary.sh
```

***

## 5. Separate “Up” and “Down” Sections (`salary-v2.sh`)

Print distinct headers for high and low salaries:

```bash theme={null}
#!/usr/bin/env bash

awk -F "|" \
  -v high_salary=90000 \
  -v low_salary=65000 \
  -v up_header="===== Needs to be adjusted up =====" \
  -v down_header="===== Needs to be adjusted down =====" '
$7 >= high_salary {
  print down_header
  print $2, $3, $7
}
$7 <= low_salary {
  print up_header
  print $2, $3, $7
}
' < employees.txt
```

***

## 6. One Header per Group (`salary-v3.sh`)

Use flags inside awk to avoid repeating headers:

```bash theme={null}
#!/usr/bin/env bash

awk -F "|" \
  -v high_salary=90000 \
  -v low_salary=65000 \
  -v up_header="===== Needs to be adjusted up =====" \
  -v down_header="===== Needs to be adjusted down =====" '
$7 <= low_salary {
  if (!printed_up_header) {
    print up_header
    printed_up_header = 1
  }
  print $2, $3, $7
}
$7 >= high_salary {
  if (!printed_down_header) {
    print down_header
    printed_down_header = 1
  }
  print $2, $3, $7
}
' < employees.txt
```

***

## 7. Parameterize with CLI Arguments (`salary-v4.sh`)

Allow users to override thresholds when running the script:

```bash theme={null}
#!/usr/bin/env bash

readonly UP_HEADER="===== Needs to be adjusted up ====="
readonly DOWN_HEADER="===== Needs to be adjusted down ====="

high_salary="${1:-90000}"
low_salary="${2:-65000}"

awk -F "|" \
  -v high_salary="$high_salary" \
  -v low_salary="$low_salary" \
  -v up_header="$UP_HEADER" \
  -v down_header="$DOWN_HEADER" '
$7 >= high_salary {
  if (!printed_down_header) {
    print down_header
    printed_down_header = 1
  }
  print $2, $3, $7
}
$7 <= low_salary {
  if (!printed_up_header) {
    print up_header
    printed_up_header = 1
  }
  print $2, $3, $7
}
' < employees.txt
```

Run with defaults:

```bash theme={null}
chmod +x salary-v4.sh
./salary-v4.sh
```

Or specify custom thresholds:

```bash theme={null}
./salary-v4.sh 80000 60000
```

***

## Next Steps

You’ve now explored:

* Pure awk vs Bash/awk hybrids
* Using `-v` to pass variables into awk
* Conditional headers with `BEGIN` and internal flags
* Parameterizing scripts via CLI

Practice customizing these scripts for different file formats, field counts, or more complex filtering logic.

***

## References

* [GNU Awk User’s Guide](https://www.gnu.org/software/gawk/manual/)
* [Bash Reference Manual](https://www.gnu.org/software/bash/manual/)
* [Advanced Bash-Scripting Guide](https://tldp.org/LDP/abs/html/)

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