root@james-desktop:~# help :
:: : Null command. No effect; the command does nothing. Exit Status: Always succeeds.
~ # : sdafsadf
~ #~ # echo sdfsadf
sdfsadf
控制调试信息输出：
#!/bin/sh
if [ -z "$SILENT" ]; then ECHO=echo else ECHO=: fi
$ECHO hello
root@james-desktop:~# cat /etc/init.d/smbd
#!/bin/sh -e # upstart-job # # Symlink target for initscripts that have been converted to Upstart.set -e
INITSCRIPT="$(basename "$0")"
JOB="${INITSCRIPT%.sh}"if [ "$JOB" = "upstart-job" ]; then
if [ -z "$1" ]; then echo "Usage: upstart-job JOB COMMAND" 1>&2 exit 1 fiJOB="$1"
INITSCRIPT="$1" shift else if [ -z "$1" ]; then echo "Usage: $0 COMMAND" 1>&2 exit 1 fi fiCOMMAND="$1"
shiftif [ -z "$DPKG_MAINTSCRIPT_PACKAGE" ]; then ECHO=echo else ECHO=: fi
$ECHO "Rather than invoking init scripts through /etc/init.d, use the service(8)"
$ECHO "utility, e.g. service $INITSCRIPT $COMMAND"case $COMMAND in
status) $ECHO $ECHO "Since the script you are attempting to invoke has been converted to an" $ECHO "Upstart job, you may also use the $COMMAND(8) utility, e.g. $COMMAND $JOB" $COMMAND "$JOB" ;; start|stop|restart) $ECHO $ECHO "Since the script you are attempting to invoke has been converted to an" $ECHO "Upstart job, you may also use the $COMMAND(8) utility, e.g. $COMMAND $JOB" PID=$(status "$JOB" 2>/dev/null | awk '/[0-9]$/ { print $NF }') if [ -z "$PID" ] && [ "$COMMAND" = "stop" ]; then exit 0 elif [ -n "$PID" ] && [ "$COMMAND" = "start" ]; then exit 0 elif [ -z "$PID" ] && [ "$COMMAND" = "restart" ]; then start "$JOB" exit 0 fi $COMMAND "$JOB" ;; reload|force-reload) $ECHO $ECHO "Since the script you are attempting to invoke has been converted to an" $ECHO "Upstart job, you may also use the $COMMAND(8) utility, e.g. $COMMAND $JOB" reload "$JOB" ;; *) $ECHO $ECHO "The script you are attempting to invoke has been converted to an Upstart" 1>&2 $ECHO "job, but $COMMAND is not supported for Upstart jobs." 1>&2 exit 1 esac