0
我已经写了印刷书籍shell脚本:逻辑或错误的Linux shell脚本
#!/bin/sh
if [ -z "$1" ]
then
exit 1
fi
filename=$1
options=""
mode="color"
first=""
last=""
pages="All pages from"
shift
until [ -z "$1" ]
do
if [ $1 = "gray" -o $1 = "grey" -o $1 = "grayscale" -o $1 = "greyscale" ]
then
options=" -o ColorModel=KGray"
mode=$1
elif [ $1 = "from" ]
then
shift
first="$1"
elif [ $1 = "to" ]
then
shift
last="$1"
fi
shift
done
if [ $first -o $last ]
then
pages="Pages"
if [ $first ]
then
pages="$pages $first"
first=" -f $first"
else
pages="$pages 1"
fi
if [ $last ]
then
pages="$pages to $last"
last=" -l $last"
else
pages="$pages to last"
fi
pages="$pages from"
fi
echo -n "$pages $filename will be printed in $mode mode. If it's OK, put paper in your printer and press ENTER. Else press CTRL+C. "
read ack
pdftops$first$last -expand $filename - | psbook | psnup -2 > tmp.ps
psselect -o tmp.ps | lpr$options
echo -n "Wait for the end of printing, then take printed pages, put them back in printer to print on other side and press ENTER again."
read ack
psselect -e -r tmp.ps | lpr$options
rm tmp.ps
exit 0
当我保存这个代码到文件“打印书”并运行它想:
print-book test.pdf gray
我得到这个:
Pages 1 to last from test.pdf will be printed in gray mode. If it's OK, put paper in your printer and press ENTER. Else press CTRL+C
即条件 “$第一-o $最后” 是真实的。但是如果在这个地方分别检查“$ first”和“$ last”,它们都是错误的。
这怎么可能?
POSIX标准建议不要使用'-o'因为这个原因,并建议使用'[...] || [']代替'[... -o ...]'。 – chepner