catch me if you can

catch_me_if_you_can/README.md

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+# Catch Me If You Can 🏃
+
+This little Bash script tries to copy a file when it has changed.
+For this, the last modification date is compared.
+A new copy is created for each change.
+The file name is `<TIMESTAMP>_<PID>`.
+
+## Installation
+
+### Download
+
+    curl -f https://raw.githubusercontent.com/Cyclenerd/toolbox/master/catch_me_if_you_can/catch_me.sh -o catch_me.sh
+
+### Configuration
+
+Edit `MY_FILE` and `MY_DIR`:
+
+    vi catch_me.sh
+
+### Run
+
+    bash catch_me.sh
+
+### Cron
+
+Execute a cron job every minute:
+
+    crontab -e
+
+Add:
+
+    */1 * * * * bash /path/to/catch_me.sh >> /dev/null

catch_me_if_you_can/catch_me.sh

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+#!/usr/bin/env bash
+
+#
+# catch_me.sh
+# Author: Nils Knieling
+#    https://github.com/cyclenerd/toolbox/catch_me_if_you_can/
+#
+# This little Bash script tries to copy a file when it has changed.
+# For this, the last modification date is compared.
+# A new copy is created for each change.
+# The file name is <TIMESTAMP>_<PID>.
+#
+
+
+#####################################################################
+#### Configuration Section
+#####################################################################
+
+# File to be monitored.
+#     If this file changes, it is copied.
+MY_FILE="/tmp/test"
+
+# Folder where the copies are saved.
+#    The folder must exist and you must have write permission.
+MY_DIR="/tmp/copy"
+
+#####################################################################
+#### END Configuration Section
+#####################################################################
+
+
+MY_TIMESTAMP_START=$(date "+%s")
+
+if [ ! -e $MY_FILE ]; then
+	echo "WARNING: '$MY_FILE' does not exist."
+	exit 2
+fi
+
+if [ ! -d $MY_DIR ]; then
+	echo "ERROR: '$MY_DIR' does not exist or no folder."
+	exit 9
+fi
+
+if [ ! -w $MY_DIR ]; then
+	echo "ERROR: No write permission on folder '$MY_DIR'."
+	exit 9
+fi
+
+# Get filename of the last copied file
+unset -v MY_LAST_FILE
+for MY_DIR_FILE in "$MY_DIR"/*; do
+	[[ $MY_DIR_FILE -nt $MY_LAST_FILE ]] && MY_LAST_FILE=$MY_DIR_FILE
+done
+
+# Compare files
+MY_FILENAME="$MY_TIMESTAMP_START""_""$$"
+if [[ $MY_FILE -nt $MY_LAST_FILE ]]; then
+	if cp "$MY_FILE" "$MY_DIR/$MY_FILENAME"; then
+		echo "INFO: '$MY_FILE' has changed. Copied to '$MY_DIR/$MY_FILENAME'."
+		exit 0
+	else
+		echo "ERROR: Can not copy file '$MY_FILE' to '$MY_DIR/$MY_FILENAME'."
+		exit 9
+	fi
+else
+	echo "INFO: '$MY_FILE' has not changed."
+	exit 1
+fi