100 lines
2 KiB
Bash
Executable file
100 lines
2 KiB
Bash
Executable file
#!/usr/bin/env bash
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set -o errexit
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set -o errtrace
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set -o nounset
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function trap_err()
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{
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echo Exiting because error occurred in script.
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}
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trap trap_err ERR
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HASH_TOOL="sha256sum"
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INTERNEL=32
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TARGET_DIR=""
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FILE=""
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function show_usage()
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{
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echo "$0 usage:"
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echo " --target-dir Directory to store the backup files"
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echo " --file The file to monitor"
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echo " --hash-tool Tools to calculate hash of file, default sha256sum"
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echo " --internel Seconds between checking file, default 32s"
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}
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function my_log()
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{
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echo "$(date --iso-8601=ns) -- $*"
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}
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function backup_the_file()
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{
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local the_file=$1
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local target="${the_file}_$(date --iso-8601=seconds --reference $the_file)"
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my_log "backuping the file to $target"
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if [ -f "$TARGET_DIR/$target" ]
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then
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my_log "$target already exists, skipped."
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else
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cp --no-target-directory $the_file $TARGET_DIR/$target
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fi
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}
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function main()
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{
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while [ "$#" -gt 1 ]
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do
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case "$1" in
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"--target-dir")
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TARGET_DIR=$2
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shift
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;;
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"--file")
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FILE=$2
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shift
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;;
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"--hash-tool")
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HASH_TOOL=$2
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shift
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;;
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"--internel")
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INTERNEL=$2
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shift
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;;
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*)
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echo unknown option: $1
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show_usage
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exit 1
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;;
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esac
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shift
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done
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if [ -z "$FILE" -o -z "$TARGET_DIR" ]
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then
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echo "option(s) --file or --target-dir is unspecified."
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exit 1
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fi
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hash_prev=""
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while [ "true" ]
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do
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hash_curr=$(eval "$HASH_TOOL $FILE")
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if [ "$hash_prev" != "$hash_curr" ]
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then
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my_log "the hash now: $hash_curr"
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backup_the_file $FILE
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hash_prev=$hash_curr
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fi
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sleep "$INTERNEL"
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done
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}
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main "$@"
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