shell脚本中. 起到了什么作用？

adminsinx

这是一个/etc/init.d/hostname.sh的脚本

#! /bin/sh ### BEGIN INIT INFO # Provides: hostname # Required-Start: # Required-Stop: # Should-Start: glibc # Default-Start: S # Default-Stop: # Short-Description: Set hostname based on /etc/hostname # Description: Read the machines hostname from /etc/hostname, and # update the kernel value with this value. If # /etc/hostname is empty, the current kernel value # for hostname is used. If the kernel value is # empty, the value 'localhost' is used. ### END INIT INFO PATH=/sbin:/bin . /lib/init/vars.sh . /lib/lsb/init-functions do_start () {     [ -f /etc/hostname ] && HOSTNAME="$(cat /etc/hostname)"     # Keep current name if /etc/hostname is missing.     [ -z "$HOSTNAME" ] && HOSTNAME="$(hostname)"     # And set it to 'localhost' if no setting was found     [ -z "$HOSTNAME" ] && HOSTNAME=localhost     [ "$VERBOSE" != no ] && log_action_begin_msg "Setting hostname to '$HOSTNAME'"     hostname "$HOSTNAME"     ES=$?     [ "$VERBOSE" != no ] && log_action_end_msg $ES     exit $ES } case "$1" in   start|"")     do_start     ;;   restart|reload|force-reload)     echo "Error: argument '$1' not supported" >&2     exit 3     ;;   stop)     # No-op     ;;   *)     echo "Usage: hostname.sh [start|stop]" >&2     exit 3     ;; esac 这里的. /lib/init/vars.sh 得到了什么？？？？？ 以下是/lib/init/vars.sh 的脚本 # # Set rcS vars # [ -f /etc/default/rcS ] && . /etc/default/rcS # Accept the same 'quiet' option as the kernel if [ ! -e /proc/cmdline ] || egrep -qw 'quiet' /proc/cmdline ; then     VERBOSE="no" fi # But allow both rcS and the kernel options 'quiet' to be overrided # when INIT_VERBOSE=yes is used as well. [ "$INIT_VERBOSE" ] && VERBOSE="$INIT_VERBOSE"

我是DBA

执行脚本

waker

1. 
   
2.         .  filename [arguments]
   
3.        source filename [arguments]
   
4.               Read  and  execute  commands from filename in the current shell
   
5.               environment and return the exit status of the last command exe-
   
6.               cuted  from  filename.   If  filename does not contain a slash,
   
7.               file names in PATH are used to find  the  directory  containing
   
8.               filename.   The  file  searched  for  in  PATH need not be exe-
   
9.               cutable.  When bash is not in posix mode, the current directory
   
10.               is  searched  if  no  file is found in PATH.  If the sourcepath
    
11.               option to the shopt builtin command is turned off, the PATH  is
    
12.               not  searched.   If any arguments are supplied, they become the
    
13.               positional parameters when filename is executed.  Otherwise the
    
14.               positional  parameters are unchanged.  The return status is the
    
15.               status of the last command exited within the script  (0  if  no
    
16.               commands  are  executed), and false if filename is not found or
    
17.               cannot be read.
    

复制代码

adminsinx

. /lib/init/vars.sh  和 sh /lib/init/vars.sh  一样吗？

我是DBA

结果一样

yezhulin1982

原帖由 adminsinx 于 2009-1-13 10:50 发表
. /lib/init/vars.sh  和 sh /lib/init/vars.sh  一样吗？

这要看从哪方面来分析。
. /lib/init/var.sh
在当前shell中执行脚本。

sh /lib/init/vars.sh
在子shell中执行脚本。
子shell中的变量不会影响到当前shell。

waker

原帖由 adminsinx 于 2009-1-13 10:50 发表
. /lib/init/vars.sh  和 sh /lib/init/vars.sh  一样吗？

不一样

Read  and  execute  commands from filename in the current shell
              environment