#!/bin/bash

dir=/home/hopper/berezin/Data
psef=/home/hopper/berezin/Data/psef
passwd=/home/hopper/berezin/Data/passwd
etcList=/home/hopper/berezin/Data/etcList
etcSlist=/home/hopper/berezin/Data/etcSlist
sol=/home/hopper/berezin/Sed

#1 change user ID, 1st word of line, form root to Master.
sed "s/^root\>/Master/" $psef > $sol/sout.01 
#sed "s/^root /Master/" $psef > $sol/sout.01

#2 Change /home/hopper to /system/tron. Don't use backslashes
sed "s#/home/hopper#/system/tron#" $passwd > $sol/sout.02

#3 Add the flag   : daemon   to end of any line belonging to a daemon
#   recognized by id endding with a d
sed "/^[^:]*d\>/ s/$/:daemon/" $passwd > $sol/sout.03

#4 copy user Id to end of line if it is a z-id, starts with z
sed "s/^\(z[^:]*\)\>.*$/& : \1/" $psef > $sol/sout.04

#5 Change 2nd occurrence of root to wheel
sed "s/root/wheel/2" $etcList > $sol/sout.05
# better, if you really are targeting the word root
sed "s/\<root\>/wheel/2" $etcList > $sol/sout.05

#6 Replace 24 contiguous spaces with 4 spaces.
#  this should affect only the 1st 24 contiguous spaces.
sed "s/ \{24\}/    /" $etcSlist > $sol/sout.06

#7 Print only lines where user id is 4-6 characters long.
sed -n "/^[^:]\{4,6\}:/p" $passwd > $sol/sout.07

#8 Write a function that tests a string for lack of spaces.

function NoSpace ()
{
   # grep may hve  -s and -q, but these are not universal
   # so redirection of output and error is more consistant
   echo "$*" | grep -v " " >/dev/null 2>&1

   # The following may be redundent.
   # testing this, I've found that if return not used, the function
   #   exits with the return code of the last executed command.
   return $?
}
 
#9 Write a function that tests a string for only digits.

function IsDigits ()
{
   echo "$*" | grep "^[0-9][0-9]*$ " >/dev/null 2>&1
   return $?
}

#10 Write a function that checks for a floating point number.
function IsFloat ()
{
  echo "$*" | grep -e "^[0-9][0-9]*\.[0-9]*$" -e "^[0-9]*\.[0-9][0-9]*$" 2> /dev/null
   return $?
}