Linux Platform - Yash-777/LearnJava GitHub Wiki

D:\MyWork\bashScript
λ mysql -u root -p -h 127.0.0.1 -P 3306
Enter password: ****
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 943
Server version: 8.0.33 MySQL Community Server - GPL

Copyright (c) 2000, 2023, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its affiliates. 
Other names may be trademarks of their respective owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> SET GLOBAL local_infile = 1;
Query OK, 0 rows affected (0.00 sec)

mysql> show variables like '%local_infile%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| local_infile  | ON    |
+---------------+-------+
1 row in set (0.03 sec)

mysql> SELECT VERSION();
+-----------+
| VERSION() |
+-----------+
| 8.0.33    |
+-----------+
1 row in set (0.00 sec)

mysql> exit;
Bye

D:\MyWork\bashScript
λ bash shellScriptBasics.sh
Usage: shellScriptBasics.sh DB_USER DB_PASS DB_NAME DATA_DIR
Example: shellScriptBasics.sh myuser mypassword myDB /path/to/data/files

D:\MyWork\bashScript
λ bash shellScriptBasics.sh root root myworkdb loadSqlFilesDir
-----------------------------------------
✅ Runtime Parameters:
DB_USER  : root
DB_PASS  : ******** (hidden for security)
DB_NAME  : myworkdb
DATA_DIR : loadSqlFilesDir
-----------------------------------------
START...
Starting at time: 2025-10-16 19:32:43
---------------------------
� Found data directory: loadSqlFilesDir
---------------------------
� Loop count: 1 | Current time: 2025-10-16 19:32:44
� Loop count: 2 | Current time: 2025-10-16 19:32:49
� Loop count: 3 | Current time: 2025-10-16 19:32:54
� Loop count: 4 | Current time: 2025-10-16 19:33:00
� Loop count: 5 | Current time: 2025-10-16 19:33:05
---------------------------
⚠️  No CSV files found in directory: loadSqlFilesDir
---------------------------
END...
Finished at: 2025-10-16 19:33:11
Total duration: 00:00:27 (hh:mm:ss)

#!/bin/bash
###############################################################################
# @file        db_import_task.sh
# @brief       Bash script to simulate database import and timed execution task
# @description
#   - Accepts database credentials and data directory as input parameters.
#   - Validates input arguments and data directory.
#   - Simulates CSV file imports (or real imports can be added).
#   - Executes a 5-iteration timed loop (1-minute each).
#   - Calculates and displays total elapsed time in hh:mm:ss format.
#
# @usage
#   ./db_import_task.sh DB_USER DB_PASS DB_NAME DATA_DIR
#   Example:
#     ./db_import_task.sh myuser mypass myDB /path/to/data
#
# @author
#   Yashwanth Merugu
###############################################################################

# -------------------------------
# Function: print_duration
# Description: Prints total duration from start to current time.
# This function is called automatically on exit.
# -------------------------------
print_duration() {
  end_time=$(date "+%Y-%m-%d %H:%M:%S")
  end_sec=$(date +%s)
  duration=$(( end_sec - start_sec ))
  hours=$(( duration / 3600 ))
  minutes=$(( (duration % 3600) / 60 ))
  seconds=$(( duration % 60 ))

  echo "---------------------------"
  echo "END..."
  echo "Finished at: $end_time"
  printf "Total duration: %02d:%02d:%02d (hh:mm:ss)\n" "$hours" "$minutes" "$seconds"
}

# Ensure duration is printed even if script exits early
trap print_duration EXIT

# -------------------------------
# Validate Required Parameters
# -------------------------------
if [ "$#" -ne 4 ]; then
  echo "Usage: $0 DB_USER DB_PASS DB_NAME DATA_DIR"
  echo "Example: $0 myuser mypassword myDB /path/to/data/files"
  exit 1
fi

# -------------------------------
# Assign Parameters to Variables
# -------------------------------
DB_USER="$1"
DB_PASS="$2"
DB_NAME="$3"
DATA_DIR="$4"

# -------------------------------
# Print Runtime Parameters
# -------------------------------
echo "-----------------------------------------"
echo "✅ Runtime Parameters:"
echo "DB_USER  : $DB_USER"
echo "DB_PASS  : ******** (hidden for security)"
echo "DB_NAME  : $DB_NAME"
echo "DATA_DIR : $DATA_DIR"
echo "-----------------------------------------"

# -------------------------------
# Capture Start Time
# -------------------------------
start_time=$(date "+%Y-%m-%d %H:%M:%S")
start_sec=$(date +%s)

echo "START..."
echo "Starting at time: $start_time"

# -------------------------------
# Step 1: Validate Data Directory
# -------------------------------
echo "---------------------------"
if [ ! -d "$DATA_DIR" ]; then
  echo "❌ ERROR: Data directory '$DATA_DIR' does not exist."
  exit 2
fi

echo "📁 Found data directory: $DATA_DIR"

# -------------------------------
# Step 2: Timed Loop (Demo Task)
# -------------------------------
echo "---------------------------"
for i in {1..5}; do
  current_time=$(date "+%Y-%m-%d %H:%M:%S")
  echo "🕒 Loop count: $i | Current time: $current_time"
  sleep 5  # Sleep for 5 seconds
done

# -------------------------------
# Step 3: Process CSV Files
# -------------------------------
echo "---------------------------"
shopt -s nullglob  # Prevents literal *.csv if no files exist
csv_files=("$DATA_DIR"/*.csv)

if [ ${#csv_files[@]} -eq 0 ]; then
  echo "⚠️  No CSV files found in directory: $DATA_DIR"
  exit 0
fi

for file in "${csv_files[@]}"; do
  echo "🚀 Importing file: $file into database $DB_NAME"
  # Simulated import command:
  # mysql -u"$DB_USER" -p"$DB_PASS" "$DB_NAME" -e \
  #   "LOAD DATA LOCAL INFILE '$file' INTO TABLE my_table FIELDS TERMINATED BY ',' LINES TERMINATED BY '\n';"
  sleep 1  # Simulate time taken for import
done

echo "✅ All files processed successfully!"
echo "---------------------------"


# -------------------------------
# Script automatically ends — trap prints duration
# -------------------------------