jhu <nomail@nomail> wrote:
> #!/bin/sh
> echo "P6 1920 1080 255" >> scene.ppm

> for ((i=1; i<=1080; i++))

  AFAIK that form of the 'for' directive is a bash extension not available
in the original sh. Hence that script is basically broken because the first
line claims it's runnable by using sh.

  (In linux systems /bin/sh is just an alias for /bin/bash, which is something
I cannot comprehend. bash is certain *not* the same thing as sh, and making
them equal only produces broken sh scripts which assume bash extensions but
still claim to be runnable using sh. The script above works, but only if if
/bin/sh is an alias for bash or another shell that supports the extension.
It won't work in systems where /bin/sh is the true original sh.)

>  cat scene_$i.ppm | sed '1,3d' >> scene.ppm

  sed '1,3d' scene_$i.ppm >> scene.ppm

-- 
                                                          - Warp

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