2012/3/20 Tom Gundersen <teg@xxxxxxx>: > 2012/3/20 郑文辉(Techlive Zheng) <techlivezheng@xxxxxxxxx>: >> But 'ls -l /bin/sh', shows that sh is a symlink to bash, but why it >> behaves so differently? >> >> lrwxrwxrwx 1 root root 4 2011-11-23 14:08 /bin/sh -> bash > > When called as "/bin/sh", bash works in compatibility mode. > Initscripts only support bash being called as "bash". > > To find out more, Google is your friend :-) > > -t Thank you, I thought it is related with this issue, so just ask here, next time, I will do my research first. I think I found the cause of my problem, it turns out I am using an very old /etc/profile. I move the /etc/profile to /etc/profile.bak and reinstall the filesystem package, then I diff the /etc/profile and /etc/profile.bak. I found my previous version of /etc/profile using the some sort of guess mechanism to find the shell that is using and 'sh' is the default value of $SHELL which may cause the last line of 'source /etc/bash-completion' running in compatibility mode. Here is the diff output. diff /etc/profile.bak /etc/profile 2,25d1 < # < # This file is intended to be used for ALL common < # Bourne-compatible shells. Shell specifics should be < # handled in /etc/profile.$SHELL where $SHELL is the name < # of the binary being run (discounting symlinks) < # < # Sections taken from SuSe's /etc/profile < # Note the explicit use of 'test' to cover all bases < # and potentially incompatible shells < < #Determine our shell without using $SHELL, which may lie < shell="sh" < if test -f /proc/mounts; then < case $(/bin/ls -l /proc/$$/exe) in < *bash) shell=bash ;; < *dash) shell=dash ;; < *ash) shell=ash ;; < *ksh) shell=ksh ;; < *zsh) shell=zsh ;; < esac < fi < < # Load shell specific profile settings < test -f "/etc/profile.$shell" && . "/etc/profile.$shell" 31c7 < PATH="/bin:/usr/bin:/sbin:/usr/sbin" --- > PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin" 34,46d9 < # Export default pkg-config path < PKG_CONFIG_PATH="/usr/lib/pkgconfig" < export PKG_CONFIG_PATH < < # Some readline stuff that is fairly common < HISTSIZE=1000 < HISTCONTROL="erasedups" < < INPUTRC="/etc/inputrc" < LESS="-R" < < export HISTSIZE HISTCONTROL INPUTRC LESS < 50c13 < test -x $profile && . $profile --- > test -r "$profile" && . "$profile" 65,66d27 < < source /etc/bash_completion