#!/bin/sh
# file: simple_fork_shell_script
# author: T. P. Baker
# last modified by: $Author$ on $Date$

# Demonstrates use of shell command language.
# To read about the features used here, use "man sh" and "man test".

echo the process number of this shell is $$

if [ $# -eq 0 ]; then 
   echo command has no parameters
else 
   echo command has $# parameters
   echo the parameters are: $@
fi

if [  \( $# -eq 1 \) -a \( "$1" = "dofork" \) ]; then
   echo doing recursive call of this script, in background
   ./simple_fork_shell_script child&
   echo waiting for child $!
   wait $! 
elif [  \( $# -eq 1 \) -a \( "$1" = "child" \) ]; then
   echo child is about to sleep for one second
   sleep 1
   echo child is done sleeping
fi

if [  \( $# -eq 1 \) -a \( "$1" = "comments" \) ]; then
cat - > tmpfile <<EOF

# When this shell script was tested on Red Hat 7.2 Linux,
# with parameter "dofork" it produced the following output:

# >./simple_fork1_shell_script dofork
# the process number of this shell is 7191
# command has 1 parameters
# the parameters are: dofork
# doing recursive call of this script, in background
# waiting for child 7192
# the process number of this shell is 7192
# command has 1 parameters
# the parameters are: child
# child is about to sleep for one second
# child is done sleeping

# Does the script work similarly on Solaris?
EOF

cat tmpfile
rm tmpfile
fi

# If the shell script is called with parameter "comments"
# it outputs the above block of comments.