Shell Script To Reverse Command Line Input / Numbers

by on October 20, 2008 · 7 comments

  1. #!/bin/bash
  2. # Write a shell program that outputs all integers upto the command line
  3. # parameter starting from 1 and also should output the same numbers 
  4. # in the reverse order.
  5. # --------------------------------------------------------------------
  6. # This is a free shell script under GNU GPL version 2.0 or above
  7. # Copyright (C) 2005 nixCraft project.
  8. # Feedback/comment/suggestions : http://cyberciti.biz/fb/
  9. # -------------------------------------------------------------------------
  10. # This script is part of nixCraft shell script collection (NSSC)
  11. # Visit http://bash.cyberciti.biz/ for more information.
  12. # -------------------------------------------------------------------------
  13. if [ $# -eq 0 ]
  14. then
  15. 	echo "$0 num1, num2, numN"
  16. 	exit 1
  17. fi
  18. x=""
  19. echo -n "Numbers are : " 
  20. for n in $@
  21. do
  22.   echo -n $n
  23.   echo -n " "
  24.   x="$n $x"
  25. done
  26. echo ""
  27. echo -n "Reverse order: "
  28. echo $x


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  • Quetzal

    if [ $# -lt 1 ]; then echo “Usage: $(basename $0) arg1 arg2 … argN “; exit 1; fi

    echo “Numbers are: $@”
    for n in $@; do x=”$n $x”; done
    echo “Reverse order: $x”

  • Aneesh

    I am getting wrong results.. Is there anything wrong???

    [root@www ~]# sh reverse.sh 3,4,9,12
Numbers are : 3,4,9,12
Reverse order: 3,4,9,12
[root@www ~]# cat reverse.sh
#!/bin/bash
# Write a shell program that outputs all integers upto the command line
# parameter starting from 1 and also should output the same numbers
# in the reverse order.
# --------------------------------------------------------------------
# This is a free shell script under GNU GPL version 2.0 or above
# Copyright (C) 2005 nixCraft project.
# Feedback/comment/suggestions : http://cyberciti.biz/fb/
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------
if [ $# -eq 0 ]
then
        echo "$0 num1, num2, numN"
        exit 1
fi
x=""
echo -n "Numbers are : "
for n in $@
do
  echo -n $n
  echo -n " "
  x="$n $x"
done
echo ""
echo -n "Reverse order: "
echo $x
[root@www ~]#
  • Arun

    Hey, CLA`s cannot be passed to the script using commas,
    sh reverse.sh 3 4 9 12

    Use space instead of comma. :)

    Cheers,
    Arun D Patil

  • Micah Trueblood

    Thanks a lot for the article.Thanks Again. Fantastic.

  • dileep

    it is so usefull for students……

  • Aryan

    Thanks This is easiest and shortest way

  • Annonymous

    Is there a way to get the result to print out on separate lines? e.g.

    Numbers are: 1 2 3 4
    Reverse Order:
    1
    2
    3
    4

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