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While loop only if a condition is met

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# 1  
Old 05-09-2011
While loop only if a condition is met
All,

I wrote the following section of code (which logically in PHP would of worked):

Code:
tmpPATH=${1}
tmpTAG=${2}
 
if [ "${tmpPATH}" == "" -a "${tmpPATH}" == "" ]
then
    while read tmpTAG tmpPATH
    do
fi 
 
echo $tmpTAG 
echo $tmpPATH 
 
if [ "${tmpPATH}" == "" ]
then
        done < ./config.cfg 
fi

When run I get the following error:

Code:
tester[5]: 0403-057 Syntax error at line 8 : `fi' is not expected.

Now I know I can write it like this (so this is not a request for another solution, but a more can the above be achieved in terms of syntax code flow - injecting the while loop) my current solution:

Code:
main_func(){
    echo $tmpTAG
    echo $tmpPATH
}
 
tmpPATH=${1}
tmpTAG=${2}
 
if [ "${tmpPATH}" == "" -a "${tmpPATH}" == "" ]
then
    while read tmpTAG tmpPATH
    do
        main_func
    done < ./config.cfg
else
    main_func
fi

# 2  
Old 05-09-2011
in main_func() you use variables that have not been declared.
The 2 lines should be put before the main_func
Code:
tmpPATH=${1}
tmpTAG=${2}

By the way instead of reading the default values from ./config.cfg to setup tmpPATH and tmpPATH you may setup this like

read default values from confi file

Code:
<./config.cfg read dT dP

Use the default setting notation :

Code:
tmpPATH=${1:-$dP}
tmpTAG=${2:-$dT}

so that if $1 and/or $2 are given, their value will be used , but if empty then the default values will be used.

example :
Code:
# cat k.cfg
defaultTag defaultPATH

Code:
# cat k

<k.cfg read dT dP

P=${1:-$dP}
T=${2:-$dT}

echo $P $T

Code:
# ksh k
defaultPATH defaultTag
# ksh k arg1 arg2
arg1 arg2
# ksh k arg1
arg1 defaultTag

# 3  
Old 05-09-2011
thanks for the reply.

Code:
tmpPATH=${1}
tmpTAG=${2}

Don't have to be before the main function, the main function can get called with either the file or passed variables.

The problem I had with the script is I want an easy way to say, if values are passed i.e.:

Code:
./tester -d /tmp/PATH -t CAD

Then just send those and don't read the ./config.cfg file. If they are empty then read the file and loop (as would be mutiple iterations in there).

So the second solution I have works (and is what I am using). What I wondered, can you have the while loop enabled depending on a condition, and if that condition is not met then just run the code which would of been in while loop.

I know I have acieved this in the second example, but from PHP I would of been able to solve it using the first method. Shell seems to require loops / cases to have to be comepleted and not cross into other if / while loops (if that makes any sense)
# 4  
Old 05-09-2011
refer to this (here below an extract)
Code:
while getopts ":ab:c" opt
do 
    case $opt in
        a ) process option -a ;;
        b ) process option -b $OPTARG is the option's argument ;;
        c ) process option -c ;;
        \? ) print 'usage: bob [-a] [-b barg] [-c] args ...' exit 1 ;;
    esac
done
shift $(($OPTIND - 1))
normal processing of arguments ...

# 5  
Old 05-09-2011
My script already utilises getops, the -d and -t can be passed or not as per my example. That allows a user to specify a certain path or use a config file if there are mutiple paths (this is a backup script). Then the final option is -b for backup, or -r for restore. Then based on the options in the file or what has been passed (-d and -t) determines the directories and the tag for the engine. The main function for backup and restore then loops through accordingly..

Like I said I have a solution just wondered if there was a way to "inject" the while loop as per the first example - like you can in other languages.
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