我在运行下面的Makefile代码时遇到了困难：
SWIG = swig
SWIG_VER = $(shell $(SWIG) -version 2>&1 | head -2 | tail -1 | cut -d' ' -f3)
SWIG_VER_NUM = $(shell echo $(SWIG_VER) | tr -d '.' | perl -lne 'chomp;while(length($$_)<4){$$_*=10}; print')
SWIG_VER_TEST = $(shell if [ $(SWIG_VER_NUM) -lt 1334 ]; then echo 1; else echo 0; fi)
获取以下错误：
Bareword found where operator expected at -e line 1, near "/usr/bin"
(Missing operator before bin?)
syntax error at -e line 1, near "/usr/bin"
syntax error at -e line 1, near ";}"
Execution of -e aborted due to compilation errors.
/bin/sh: line 0: [: -lt: unary operator expected
可能错误地转义了perl的默认变量......
注意：
SWIG版本输出（包括新行）：
> swig -version
SWIG Version 2.0.1
Compiled with g++ [x86_64-unknown-linux-gnu]
Configured options: +pcre
Please see http://www.swig.org for reporting bugs and further information
SWIG_VER行输出：
> swig -version 2>&1 | head -2 | tail -1 | cut -d' ' -f3
2.0.1