Bash diff 在找到第一个差异时停止

Question

我有这个用于备份的脚本。问题是它有点慢。我想知道是否有 diff 命令在找到第一个差异时停止。

DocumentsFiles=("Books" "Comics" "Distros" "Emulators" "Facturas" "Facultad" "Laboral" "Mods" "Music" "Paintings" "Projects" "Scripts" "Tesis" "Torrents" "Utilities")
OriginDocumentsFile="E:\Documents\"
DestinationDocumentsFile="F:\Files\Documents\"

## loop file to file and copy in backup
for directory in "${DocumentsFiles[@]}"
do
    RealOrigin="${OriginDocumentsFile}${directory}"
    RealDestination="${DestinationDocumentsFile}${directory}"

    echo $directory
    if [ -a "$RealDestination" ]; then
        echo ok
        if diff -r $RealOrigin $RealDestination; then
            echo "${directory} are equal!"
        else
            rm -rfv $RealDestination
            cp -ruv $RealOrigin "${DestinationDocumentsFile}"
        fi
    else 
        cp -ruv $RealOrigin "${DestinationDocumentsFile}"
    fi
done

Answer 1

diff -q 报告 "only when files differ"（根据 man diff），所以我相信它会在第一次差异后停止。

但这有点XY problem。你真的需要一个更好的备份程序，比如 rsync:

It is famous for its delta-transfer algorithm, which reduces the amount of data sent over the network by sending only the differences between the source files and the existing files in the destination.

来自man rsync

Bash diff 在找到第一个差异时停止

Bash diff that stops when it finds the first difference

bash

diff