BATCH FOR 循环但从特定文件开始

Question

我在Windows10 中有多个文件夹，每个文件夹包含多个PDF 文件。对于每个文件夹，我需要运行 GhostScript 将文件夹的 PDF 文件作为输入，但将某个文件作为第一个文件。

每个文件夹都包含一个名为 "FirstFile-X.pdf" 的文件，其中 X 可以是任何东西，对于每个文件夹，我需要将该文件作为第一个输入。

我在批处理文件中有以下内容：

setlocal enableDelayedExpansion
set gs="C:\Program Files\gs\gs9.54.0\bin\gswin64.exe"
set options=-dNOPAUSE -q -dBATCH -sDEVICE=pdfwrite
%gs% -sDEFAULTPAPERSIZE=a4 -dBATCH
for /d %%d in (*) do (
    set a=
    set output=%%d.pdf
    for %%f in (%%d\*.pdf) do (
        set "a=!a!%%d^\%%~nxf "
    )
    %gs% %options% -sOutputFile=!output! !a!
)

以上代码有效，但它没有将特定文件作为第一个输入。是否可以让最里面的 for-loop 运行按照我需要的顺序遍历每个文件？

Answer 1

您可以使用一个额外的 for 循环，它只迭代匹配模式 FirstFile-*.pdf 的第一个文件（预计只有一个匹配）。该文件可以排除在另一个已经存在的 for 循环中。见代码中的解释性rem注释：

@echo off
setlocal EnableExtensions EnableDelayedExpansion
rem // Use quoted `set` syntax to assign unquoted values but still protect special characters:
set "gs=C:\Program Files\gs\gs9.54.0\bin\gswin64.exe"
set "options=-dNOPAUSE -q -dBATCH -sDEVICE=pdfwrite"
rem // Use quotation during expansion of variables:
"%gs%" -sDEFAULTPAPERSIZE=a4 -dBATCH

for /D %%d in (*) do (
    set "a="
    rem // Let an extra loop find the first file:
    for %%e in ("%%d\FirstFile-*.pdf") do (
        rem /* This condition is just necessary in case more than one files are found
        rem    by the extra loop in order to avoid duplicates in the returned list: */
        if not defined a (
            rem // Append the first file:
            set "a=!a!%%~e "
            rem // Iterate over all files (including first file):
            for %%f in ("%%d\*.pdf") do (
                rem // Exclude already processed first file at this point:
                if /I not "%%~NXf"=="%%~NXe" set "a=!a!%%~f "
            )
        )
    )
    rem // There is no variable `output` needed:
    "%gs%" %options% -sOutputFile=%%d !a!
)
endlocal
exit /B

此外，我还做了一些其他的小改进，代码中也有注释。

请注意，此代码在包含空格的目录和 PDF 文件路径以及包含字符 ! 和 ^ 的情况下仍然会遇到问题。为了克服它们，您将需要进一步报价和延迟扩展的切换：

@echo off
setlocal EnableExtensions DisableDelayedExpansion
rem // Use quoted `set` syntax to assign unquoted values but still protect special characters:
set "gs=C:\Program Files\gs\gs9.54.0\bin\gswin64.exe"
set "options=-dNOPAUSE -q -dBATCH -sDEVICE=pdfwrite"
rem // Use quotation during expansion of variables:
"%gs%" -sDEFAULTPAPERSIZE=a4 -dBATCH

for /D %%d in (*) do (
    set "a="
    set "output=%%d"
    rem // Let an extra loop find the first file:
    for %%e in ("%%d\FirstFile-*.pdf") do (
        rem // Store currently iterated item:
        set "item=%%~e"
        rem /* This condition is just necessary in case more than one files are found
        rem    by the extra loop in order to avoid duplicates in the returned list: */
        if not defined a (
            rem // Toggle delayed expansion to avoid issues with `!` and `^`:
            setlocal EnableDelayedExpansion
            rem // Append the first file in a quoted manner:
            set "a=!a!"!item!" "
            rem // Transfer value `a` over `endlocal` barrier:
            for /F "delims=" %%t in ("a=!a!") do endlocal & set "%%t"
            rem // Iterate over all files (including first file):
            for %%f in ("%%d\*.pdf") do (
                rem // Store currently iterated item:
                set "item=%%~f"
                rem // Exclude already processed first file at this point:
                if /I not "%%~NXf"=="%%~NXe" (
                    rem // Toggle delayed expansion to avoid issues with `!` and `^`:
                    setlocal EnableDelayedExpansion
                    rem // Append the current item in a quoted manner:
                    set "a=!a!"!item!" "
                    rem // Transfer value `a` over `endlocal` barrier:
                    for /F "delims=" %%t in ("a=!a!") do endlocal & set "%%t"
                )
            )
        )
    )
    rem // Eventually use delayed expansion as well as quotation:
    setlocal EnableDelayedExpansion
    "!gs!" !options! -sOutputFile="!output!" !a!
    endlocal
)
endlocal
exit /B

Answer 2

@aschipfl 给出的答案启发了我做一个不同的解决方案：

@echo off
setlocal enableDelayedExpansion
set "gs=C:\Program Files\gs\gs9.54.0\bin\gswin64.exe"
set "options=-dNOPAUSE -q -dBATCH -sDEVICE=pdfwrite"
"%gs%" -sDEFAULTPAPERSIZE=a4 -dBATCH
for /d %%d in (*) do (
    set a=
    for %%f in (%%d\*.pdf) do (
        set string=%%~nf
        if "!string:~0,5!"=="First" (
            set "a=%%f !a!"
        ) else (
            set "a=!a!%%f "
        )
    )
    "%gs%" %options% -sOutputFile=%%d.pdf !a!
)
endlocal

我只是将文件名添加到字符串 a 的开头，如果文件名以“First”开头，如果不是，则将文件名添加到字符串的末尾 a。我还实施了@aschipfl 建议的其他一些小改动。

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