exec grep -E ${1+"$@"} 怎么理解??

devil123456789

#!/bin/sh
exec grep -E ${1+"$@"}
各位大侠 这条命令应该如何分析理解?

yongjian

Post by devil123456789
#!/bin/sh
exec grep -E ${1+"$@"}
各位大侠 这条命令应该如何分析理解?

In shell, its called Parameter Substitution. abs has detail explanation. (page 85)