shell实例收集

实例:

case $UNAME in
  "Linux")
      HOST=`hostname -s 2>/dev/null`
      RET=$?
      if [ $RET != 0 ]; then
          HOST=`hostname`
          echo "WARN: hostname -s failed, use '$HOST' as hostname" > /dev/stderr
      fi
      ;;
case

set命令:

说明:
    The -- is the standard "don't treat anything following this as an option"
    parameters which follow this option do not set shell flags, but are assigned to positional parameters

实例:
$ set a b c
$ echo $1,$2,$3
a,b,c
======
$ echo $1,$2,$3
a,b,c
$ set -- haproxy "$@"
$ echo $1,$2,$3,$4
haproxy,a,b,c
======
$ set -a b
$ echo $1
b
----
$ set -- -a b
$ echo $1
-a