bash - 带有 awk 的这个 shell 脚本行的含义

Question

我在 [linux device drivers] 一书中读到了这行脚本。它有什么作用？

major=$(awk "\\$2=  =\"$module\" {print \\$1}" /proc/devices)

在上下文中:

#!/bin/sh
module="scull"   
device="scull"  
mode="664"

# invoke insmod with all arguments we got  
# and use a pathname, as newer modutils don't look in . by default

/sbin/insmod ./$module.ko $* || exit 1


# remove stale nodes  
rm -f /dev/${device}[0-3]   

major=$(awk "\\$2=  =\"$module\" {print \\$1}" /proc/devices)

mknod /dev/${device}0 c $major 0
....

Answer 1

更好的写法是:

major=$(awk -v mod=$module '$2==mod{print $1}' /proc/devices)