I'm something of an amateur when it comes to Bash shell scripting and am baffled by this first line in the killproc() function in /etc/init.d/functions on a CentOS 5.10 system:
local RC killlevel= base pid pid_file= delay try
What is the meaning of that line? I believe it is the declaration of local variables perhaps, but what is the meaning of the = after a couple of the items? I have included the complete killproc() function below for reference:
# A function to stop a program.
killproc() {
local RC killlevel= base pid pid_file= delay try
RC=0; delay=3; try=0
# Test syntax.
if [ "$#" -eq 0 ]; then
echo $"Usage: killproc [-p pidfile] [ -d delay] {program} [-signal]"
return 1
fi
if [ "$1" = "-p" ]; then
pid_file=$2
shift 2
fi
if [ "$1" = "-d" ]; then
delay=$(echo $2 | awk -v RS=' ' -v IGNORECASE=1 '{if($1!~/^[0-9.]+[smhd]?$/) exit 1;d=$1~/s$|^[0-9.]*$/?1:$1~/m$/?60:$1~/h$/?60*60:$1~/d$/?24*60*60:-1;if(d==-1) exit 1;delay+=d*$1} END {printf("%d",delay+0.5)}')
if [ "$?" -eq 1 ]; then
echo $"Usage: killproc [-p pidfile] [ -d delay] {program} [-signal]"
return 1
fi
shift 2
fi
# check for second arg to be kill level
[ -n "${2:-}" ] && killlevel=$2
# Save basename.
base=${1##*/}
# Find pid.
__pids_var_run "$1" "$pid_file"
if [ -z "$pid_file" -a -z "$pid" ]; then
pid="$(__pids_pidof "$1")"
fi
# Kill it.
if [ -n "$pid" ] ; then
[ "$BOOTUP" = "verbose" -a -z "${LSB:-}" ] && echo -n "$base "
if [ -z "$killlevel" ] ; then
if checkpid $pid 2>&1; then
# TERM first, then KILL if not dead
kill -TERM $pid >/dev/null 2>&1
usleep 100000
if checkpid $pid ; then
try=0
while [ $try -lt $delay ] ; do
checkpid $pid || break
sleep 1
let try+=1
done
if checkpid $pid ; then
kill -KILL $pid >/dev/null 2>&1
usleep 100000
fi
fi
fi
checkpid $pid
RC=$?
[ "$RC" -eq 0 ] && failure $"$base shutdown" || success $"$base shutdown"
RC=$((! $RC))
# use specified level only
else
if checkpid $pid; then
kill $killlevel $pid >/dev/null 2>&1
RC=$?
[ "$RC" -eq 0 ] && success $"$base $killlevel" || failure $"$base $killlevel"
elif [ -n "${LSB:-}" ]; then
RC=7 # Program is not running
fi
fi
else
if [ -n "${LSB:-}" -a -n "$killlevel" ]; then
RC=7 # Program is not running
else
failure $"$base shutdown"
RC=0
fi
fi
# Remove pid file if any.
if [ -z "$killlevel" ]; then
rm -f "${pid_file:-/var/run/$base.pid}"
fi
return $RC
}
It's just declaring a lot of function scope variables, where killlevel
and pid_file
are assigned the empty string and the others are not assigned anything.
There is a slight difference. local
variables are also visible in functions called from the function. So if you happen to call killproc()
recursively, the uninitialized ones are remembered from the caller.
On Debian the lib/lsb/init-functions
file looks like this:
killproc() {
local pidfile sig status base name_param is_term_sig OPTIND
pidfile=
name_param=
is_term_sig=
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