eval and variable assignment

Shell Programming and Scripting
1

Hi,

i have an issue with eval and variable assignment.

1) i have a date value in a variable and that date is part of a filename,
var1=20100331
file1=${var1}-D1-0092.xml.zip
file2=${var2}-D2-0092.xml.zip
file3=${var3}-D3-0092.xml.zip
i am passing the above variables to a script via commandline and assigning the values of these
variables to another set of variables using while get opts command as below,

f\) eval FILE=\\$$\{OPTARG\}
	FILES="$FILE $FILES";;

Issue - the array variable FILES is not populated with filenames here.

2) Issue with filenames - I have filenames which consists of spaces and special characters.
eg: REP - inven - 1.TXT
I am using same concept as above. i.e. passing variables to script. i am getting error
with eval command.

Please advise in both scenarios on how to avoid issues.

Thanks in advance..

Regards,
Mohan

2

Please post the entire script.

3

To populate an array the correct syntaxes are:

ARRAY=( "Elem1" "Elem 2" "Third element" "Four has index 3" )
# or
ARRAY[$index]="Element X"

Try to put quotes + escaped quotes

eval "FILE=\"\$${OPTARG}\""
4

Hi Frans,

Thank you very much. First step is working for me.

regarding the step#2, i maintain all the job related variables in a config script which gets evaluated at the start of every job. The below variables are giving error while evaluating,

Var1="REP0022 - Yesterday's account savings_ 1.TXT"

Error :
ksh -: not found

I tried enclosing above filename in single quotes but of no use.

Thanks in advance.

Regards,
Mohan

5

You should initialize the variable like

STRING="Var1=\"REP0022 - Yesterday's account savings_ 1.TXT\""
eval "$STRING"
6

HI Frans,

Thank you. I am able to assign the filenames to a variable now . I have 3 variables like this. all of these are assigned to an array. i am able to get part of the filename (i.e. till the space as a value)while retrieving .

Following is the code :

storing the values in FILES string after we receive the values from commandline,
f) eval FILE=\"\$${OPTARG}\"
FILES="$FILE $FILES";;

assigning the FILES string to an array : set -A filesToGet $FILES

Retrieving each file from the array : file=${filesToGet[$curFileIndex]}

but this way it is considering only part of the filename.i.e. till the first space as a first filename. Please suggest how can i retrive the whole filename i.e. REP00029 - Yesterdays Postings Total_ 1.TXT

Once again thanks in advance..

Regards,
Mohan

7

Maybe you should directly construct the array like this:

# to add $FILE (string) to $FILES (array)
$FILES[${#FILES[@]}]="$FILE" # ${#FILES[@]} gives the nb of elements in the array => the first empty index (first is 0)
8

Hi Frans,

i am passing 3 variables(which contain filenames) to the script and storing these in a string called FILES. Here FILES is not an array.later i am assigning this string FILES to an array using set -A definition. Please advise on how to retrieve the whole filename at once after i assign the FILES string to an array.

Regards,
Mohan

9

What i meant is building an array (FilesToGet) in place of a string, so you won't need to use the set -A.
what is the result of ?

for ((i=0; i<${#FilesToGet[@]}; i++))
do
    echo "$i - ${FilesToGet[$i]}"
done

It would be fine if you post the entire script (between code tags!)

10

Hi Frans,

Please find the code below enclosed between dashed lines.what is a code tag?

-------------------------------------------------

#!/usr/bin/ksh -p
 
 #set -v -x
 
# Source OpUtils environment
eval $(/opt/PROpUtils/default/bin/Prism)
 
# Source gmi environment
eval $(/opt/PRgmi/default/bin/Prism)
 
while getopts p:u:i:l:r:f:c:w:d: name
do
    case $name in
    p)    PROCESSNAME=${OPTARG};;
    u)    eval USERHOST=\$${OPTARG};;
    i)    eval USERID=\$${OPTARG};;
    l)    eval LOCALDIR=\$${OPTARG};;
    r)    eval REMOTEDIR=\$${OPTARG};;
    f)    eval FILE=\"\$${OPTARG}\"
          FILES="\"$FILE\" $FILES";;
    c)    eval COPYPREFIX=\$${OPTARG};;
    w)    eval WAITSECS=\$${OPTARG};;
    d)    eval DURATION=\$${OPTARG};;
    \?)   printf "Usage: %s: [-p process name] [-u user@hostname] [-i userid][-l localdir] [-r remotedir] [-f file(s)] [-c prefix locally] [-w retrywait secs] [-d durat
ion] \n" $0
          exit 2;;
    esac
done
shift $(($OPTIND - 1))
 
echo "Getting Password "
 

 
if [ -f ${LOCALDIR}/../locks/${PROCESSNAME}.lock ] ; then
if kill -0 $(<${LOCALDIR}/../locks/${PROCESSNAME}.lock); then
kill $(<${LOCALDIR}/../locks/${PROCESSNAME}.lock)
fi
fi
 
TMPFILE=/var/tmp/${PROCESSNAME}.tmp
print $$ >${LOCALDIR}/../locks/${PROCESSNAME}.lock
 
print "`date` - Started - Getting $FILES\nremote: $USERHOST:$REMOTEDIR\nlocal: $LOCALDIR\n";
 
set -A filesToGet $FILES
 
totalFiles=${#filesToGet[@]}
 
until [[ ${#filesToGet[@]} -eq 0 ]];do
 
if [ ${TIMEELAPSED} ]
then
   print "`date` - Sleep Time Elapsed: ${TIMEELAPSED}\n"
else
   integer TIMEELAPSED=0
fi
 
if [ $TIMEELAPSED -gt $DURATION ]
then
    print "There were still ${#filesToGet[@]} file(s) to get therefore exiting with exit status 1."
    exit 1
fi
 
curFileIndex=0
 
while [[ $curFileIndex -lt $totalFiles ]];do
 
file=${filesToGet[$curFileIndex]}
 
if [ $file ]
then
        echo In $file if condition
        if [ ! -f ${LOCALDIR}/../locks/${file}.lock ]; then
                print $$ >${LOCALDIR}/../locks/${file}.lock
        fi
 
        echo " $WGET_HOME/wget --no-check-certificate --user=${USERID} --password=${SERVER_PASSWORD} -O ${LOCALDIR}/${file} ${USERHOST}/${REMOTEDIR}/${file}"
$WGET_HOME/wget --no-check-certificate --user=${USERID} --password=${SERVER_PASSWORD} -O ${LOCALDIR}/${file} ${USERHOST}/${REMOTEDIR}/${file}
 
        EXIT_STATUS=$?
        echo "Exit status"$EXIT_STATUS
 
        if [[ $EXIT_STATUS -eq 1 ]]
        then
                echo "`date` - The file $file was not available."
        else
        if [ $EXIT_STATUS -ne 0 ]
        then
                echo "`date` - Wget failed and returned exit code: $EXIT_STATUS"
                exit 2
        else
 
                echo "`date` - Got file ${file}."
                unset filesToGet[$curFileIndex]
 
                if [ $COPYPREFIX ]
                then
                        echo "`date` - Now moving file ${file} to $COPYPREFIX$file"
                        mv ${LOCALDIR}/${file} ${LOCALDIR}/${COPYPREFIX}${file}
                fi
 
         fi
        fi
fi
 
        curFileIndex=$curFileIndex+1
 
        echo Removing lock file
        rm -f ${LOCALDIR}/../locks/${file}.lock
 
done
 
if [[ ${#filesToGet[@]} -ne 0 ]]
then
    if [ $WAITSECS ]
    then
       sleep $WAITSECS
       integer TIMEELAPSED=$TIMEELAPSED+$WAITSECS
    fi
fi
done
print "`date` - **** Finished ****"
 
rm -f ${LOCALDIR}/../locks/${PROCESSNAME}.lock
 
exit 0

--------------------------------------------------

edit by bakunin: after the explanation frans gave you I'm sure you bring your own code-tags to the party, won't you?

11

For code tags :

  1. select the text you want to be displayed as code
  2. click on the '#' button in toolbar of the editor.

You could replace

f)    eval FILE=\"\$${OPTARG}\"
          FILES="\"$FILE\" $FILES";;

by the following statement

f) eval $FILES[${#FILES[@]}]=\"\\"$OPTARG\\"\"

and in the line

print "`date` - Started - Getting $FILES\nremote:  $USERHOST:$REMOTEDIR\nlocal: $LOCALDIR\n";
# replace $FILES by ${FILES[*]} (to treat $FILES as an array)

Are all the eval statements really necessary ? (for USERHOST, LOCALDIR ...)
couldn't you proceed as for the first parameter like

VARNAME=${OPTARG};;
12

This won't work in any way: when you store the various elements in a string you have to separate them somehow so that you can later split the string into array elements. Since you said above that your filenames can contain blanks i am at a loss which delimiter character you want to use.

I hope this helps.

bakunin