BASH脚本：代码可在终端上运行，但不能从rc.local上运行

Question

I've written a small script that ping's an address and then mounts the device at that address if the ping returned successful. The file is located in rc.local on a Ubuntu Linux System.

It works great if run from a terminal (as root), but won't run from rc.local at boot. I know it's being executed because /tmp/buffalo_mount.log contains "Executing Network Device Detect Script From rc.local". Anyone got any ideas?

NOTE: Now working! Please read notes below :-)

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

ADDRESS=192.168.1.101
DATETIME="$(date)"
LOGFILE="/tmp/buffalo_mount.log"

sleep 30s

echo "Executing Network Device Detect Script From rc.local" >> $LOGFILE
    if /bin/ping -c 1 -t 1 $ADDRESS > /tmp/ping 2>&1 ;then  # check the exit code
        echo "$ADDRESS is LIVE  "+$DATETIME >> $LOGFILE # display the output
    # Ping reply was good, so run the mount command.
    echo "Slept, now mounting device" >> $LOGFILE
    /bin/mount /media/Buffalo/Acer-laptop-back_in_time
    else
        echo "$ADDRESS is DEAD  "+$DATETIME >> $LOGFILE
fi

Then I had to edit the '/etc/fstab' file so the fstab knows about the mount, but doesn't mount until told to by my script above, using the ' noauto ' parameter. My example in fstab is:-

//192.168.1.101/back-in-time/ /media/Buffalo/Acer-laptop-back_in_time cifs **noauto**,guest,uid=1000,iocharset=utf8,codepage=unicode,unicode,_netdev  0  0

Really hope this help someone because it was driving me nuts. Thanks to all those that helped.

Answer 1

The -e argument asks sh to exit if a command have a non 0 exist status, thus the script will stop instead of executing the else branch of your if. You should replace

/bin/ping -c 1 -t 1 $ADDRESS > /dev/null 2> /dev/null  # ping and discard output
if [ $? -eq 0 ] ; then

by

if /bin/ping -c 1 -t 1 $ADDRESS > /dev/null 2>&1 ; then