diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 338f71a05..fa1081c5c 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -375,7 +375,7 @@ jobs:
         shell: msys2 {0}
         run: |
           cmake --install ${{ env.BUILD_DIR }}
-          Get-Content ${{ env.BUILD_DIR }}/install_manifest.txt | %{ $_.TrimStart('${{ env.INSTALL_DIR }}') } | %{ $_.TrimStart('./') } | Out-File -Append -FilePath ${{ env.INSTALL_DIR }}/manifest.txt 
+          while read l; do l=${l#${{ env.INSTALL_DIR }}}; l=${l#./}; echo $l; done < ${{ env.BUILD_DIR }}/install_manifest.txt >> ${{ env.INSTALL_DIR }}/manifest.txt 
 
       - name: Package (Windows MSVC)
         if: runner.os == 'Windows' && matrix.msystem == ''
@@ -413,7 +413,7 @@ jobs:
         run: |
           cp -r ${{ env.INSTALL_DIR }} ${{ env.INSTALL_PORTABLE_DIR }}  # cmake install on Windows is slow, let's just copy instead
           cmake --install ${{ env.BUILD_DIR }} --prefix ${{ env.INSTALL_PORTABLE_DIR }} --component portable
-          Get-Content ${{ env.BUILD_DIR }}/install_manifest_portable.txt | %{ $_.TrimStart('${{ env.INSTALL_DIR }}') } | %{ $_.TrimStart('./') } | Out-File -Append -FilePath ${{ env.INSTALL_DIR }}/manifest.txt
+          while read l; do l=${l#${{ env.INSTALL_DIR }}}; l=${l#./}; echo $l; done < ${{ env.BUILD_DIR }}/install_manifest_portable.txt >> ${{ env.INSTALL_DIR }}/manifest.txt 
 
       - name: Package (Windows MSVC, portable)
         if: runner.os == 'Windows' && matrix.msystem == ''