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Using arrays in bash using strings to bash built-in true

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Top Forums Shell Programming and Scripting Using arrays in bash using strings to bash built-in true
# 15  
Old 03-28-2012
You're always so fast, and I have a habit of editing in minor fixes later. Check my post again.

Code:
[ ! -z "$1" ]

vs
Code:
[ ! -z "${!1}" ]

# 16  
Old 03-28-2012
Quote:
Originally Posted by Corona688
I don't think you need any of them at all. You can tell if the variables are blank, why waste more variables storing things you can tell without them?

Also -- just set your defaults in the first place, and let the script change them later if they're given.

Code:
OLDIFS="$IFS"
IFS="|="                # IFS controls splitting. Split on "|" and "=", not whitespace.
set -- $*               # Set the positional parameters to the command line arguments.
IFS="$OLDIFS"

# Just set the default in the first place.
value_cmodIfl="$dflt_cmodIfl"

while [ "$#" -gt 0 ]
do
  case "$1" in

  "--"[cC][mM][oO][dD]|\
  "--"[cC][mM][oO][dD]"-"[iI][fF][lL])
    shift
    value_cmodIfl="$1"
  ;;

  "--"[sS][rR][cC][sS]|\
  "--"[sS][rR][cC][sS]"-"[iI][fF][lL])
    shift
    value_srcsIfl="$1"
  ;;

  "--"[rR][cC][vV][sS]|\
  "--"[rR][cC][vV][sS]"-"[iI][fF][lL])
    shift
    value_rcvsIfl="$1"
  ;;

  *)
    value_bdFileLst="$value_bdFileLst $1"
  ;;

  esac

  shift                 # Skip ahead to the next argument

done

if [ ! -z "$value_rcvsIfl" ]
then
        echo "rcvsIfl given"
fi


I agree with you. One problem is that some defaults require the use of mandatory values defined by the user, so I cannot put them all at the beginning. The result was that some defaults occurred in the beginning and some after the while loop. This used to be ok, but when amount of options got larger, it seems a good idea to group them all after the while loop.

---------- Post updated at 01:16 PM ---------- Previous update was at 01:08 PM ----------

Quote:
Originally Posted by Corona688
I think functions may be helpful to you in simplifying your code, and making it look better to you. In BASH and some KSH you can do this:

Code:
function isset # varname
{
        [ -z "${!1}" ]
}

function notset # varname
{
        [ ! -z "${!1}" ]
}

if isset VARIABLE # Note the lack of $
then
        echo "VARIABLE is set, its value is $VARIABLE"
fi

if notset VARIABLE
then
        echo "VARIABLE is not set"
fi

Seems to work now with the following modifications
Code:
function isSet
{
    [ ! -z "${!1}" ]
}

function notSet
{
    [ -z "${!1}" ]
}

# 17  
Old 03-28-2012
If you have lots and lots of optional, default, and mandatory values, you can do something like this:

Code:
# File listing variables and default values
# Mandatory value causes error if not set, printing errormessage from file
var1 mandatory errormessage
# Optional variable gets set to defaultvalue when absent
var2 optional defaultvalue
var3 optional defaultvalue
var4 optional defaultvalue

Code:
while read VAR TYPE STR
do
        [ -z "$VAR" ] && continue # Skip blank lines
        [ "${VAR:0:1}" = "#" ] && continue # Skip comments

        case "$TYPE" in
        mandatory)
                if [ -z "${!VAR}" ] # Blank variable is an error
                then
                        echo "$VAR not set:  $STR"
                        exit
                fi
                ;;

        *)        # If blank, set default
                   # <<< is a BASH-only syntax.
                   [ -z "${!VAR}" ] && read VAR <<<"$STR"
                ;;
        esac
done < variablefile

Last edited by Corona688; 03-28-2012 at 03:26 PM..
# 18  
Old 03-28-2012
Quote:
Originally Posted by Corona688
If you have lots and lots of optional, default, and mandatory values, you can do something like this:

Code:
# File listing variables and default values
# Mandatory value causes error if not set, printing errormessage from file
var1 mandatory errormessage
# Optional variable gets set to defaultvalue when absent
var2 optional defaultvalue
var3 optional defaultvalue
var4 optional defaultvalue

Code:
while read VAR TYPE STR
do
        [ -z "$VAR" ] && continue # Skip blank lines
        [ "${VAR:0:1}" = "#" ] && continue # Skip comments

        case "$TYPE" in
        mandatory)
                if [ -z "${!VAR}" ] # Blank variable is an error
                then
                        echo "$VAR not set:  $STR"
                        exit
                fi
                ;;

        *)        # If blank, set default
                   # <<< is a BASH-only syntax.
                   [ -z "${!VAR}" ] && read VAR <<<"$STR"
                ;;
        esac
done < variablefile

Having a bit of difficulty seeing where this fits in.

I use the script in the following way:

Code:
cd testPath
/thePath/script.bash/raytrac.bash --cmod=file.cmod

In this case the program will search in directory testPath for files
Code:
.srcs and .rcvs

Other options, for example:
Quote:
nameOfl
This is either set by the user using --nameOfl=name or take the name of the cmod file (call it cmodName) to create the
Code:
raysOfl="cmodName.ry" and trvtOfl="cmodName.xt"

# 19  
Old 03-28-2012
That won't do what you want then, no.
# 20  
Old 03-28-2012
I do not want the user to input the options interactively. The idea is that the user sets up a script with the sequence of operations he wants (run scripts and C++ programs), run the script, and no user requests are ever done. He then waits for the script to finish. In the meantime, he can check and do some analysis of the results as the sequence progresses.
# 21  
Old 03-28-2012
My script wasn't interactive.

It was just one way to do a loop, so instead of doing a million lines of "if this variable is blank, then set that default" you repeat one loop a million times on different values.
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