UNIX for Advanced & Expert Users

$ cat test.ksh
#! /bin/ksh
print "Executed on OS: $( uname -rsv )" > test.out
( echo "line 1"; echo "middle line"; echo "last one" ) |
awk '
  BEGIN {
    re="iddl"
  }
  $0 ~ re {
    print "From awk: " $0
  }
' >> test.out 2>&1
$ ./test.ksh
$ cat test.out
Executed on OS: AIX 3 5
From awk: middle line

$ cat test.out
Executed on OS: SunOS 5.10 Generic_141414-07
awk: syntax error near line 5
awk: bailing out near line 5

$ cat test_const.ksh
#! /bin/ksh
print "Executed on OS: $( uname -rsv )" > test_const.out
( echo "line 1"; echo "middle line"; echo "last one" ) |
awk '
  $0 ~ /iddl/ {
    print "From awk: " $0
  }
' >> test_const.out 2>&1
$ ./test_const.ksh
$ cat test_const.out
Executed on OS: SunOS 5.10 Generic_141414-07
From awk: middle line

case $OS in
     Solaris)
          PATH=$PATH:/usr/xpg4/bin
          ;;

     AIX)
          PATH=$PATH:/usr/bin
          ;;

esac