[Bash] problem with script in sed command

[icui]

I made a little script that searches and substitutes parameters in a configuration file but I've a problem:

Configuration file:

conf.tmp

parametro1=mario
parametro2=ugo
parametro3=elena
parametro4=sara

Script:

#!/bin/bash -x

TMP_FILE=./test.tmp
CONF_FILE=./conf.tmp
TOT_PARAMETERS=$#;
scratch=""

if test $[TOT_PARAMETERS%2] -ne 0
then
        echo "Usage: $0 desc"
        exit 1
fi

if test $# -lt 2
then
        echo "Usage: $0 desc"
        exit 1
fi

ctr=0
until [ -z "$1" ]  
do
  PARAMETER=$1
  NEW_VALUE=$2
  if test ${ctr} -eq 0
  then
    scratch="sed \"s%^$PARAMETER=.*%${PARAMETER}=${NEW_VALUE}%g\" "
  else
    scratch="${scratch} | sed \"s%^$PARAMETER=.*%${PARAMETER}=${NEW_VALUE}%g\" "
  fi
  let ctr=ctr+1
  shift 2
done

echo -e ""
echo "COMMAND LINE: cat ${CONF_FILE} | ${scratch} > $TMP_FILE";
echo -e ""

cat ${CONF_FILE} | ${scratch} > $TMP_FILE

# ... continua

executing the script:

:~$ ./script.sh  parametro1 pippo parametro2 pluto parametro3 paperino

look the output, the printed command line is correct but it works only if executed out of the script.
The same command in the script fails.

Command line:

cat ./conf.tmp | sed "s%^parametro1=.*%parametro1=pippo%g"  | sed "s%^parametro2=.*%parametro2=pluto%g"  | sed "s%^parametro3=.*%parametro3=paperino%g"  > ./test.tmp

in debug mode I look that:

sed '"s%^parametro1=.*%parametro1=pippo%g"' '|' sed '"s%^parametro2=.*%parametro2=pluto%g"' '|' sed '"s%^parametro3=.*%parametro3=paperino%g"'

sed: -e expression #1, char 1: Unknown command: `"'

Any hints?

Ps. Sorry for my terrible english ;)

[gritty]

I don't think I follow your problem, what exactly are you trying to do with sed?
You said it works form the command line but not in the script?

[icui]

You said it works form the command line but not in the script?

exactly,

this line works fine:

cat $filename | sed "s%^p1=.*%p1=v1%g" | sed "s%^p2=.*%p2=v2%g" > $filetarget

But in the script same command fails because the command line it's changed in:

sed '"s%^p1=.*%p1=v1%g"' '|' sed '"s%^p2=.*%p2=v2%g"'

look the argument of sed all with added single quote, also the pipe.

here the solution at problem:

cmd=""
while [ -n "$1" ]
do
        cmd="${cmd}s%^$(printf "%q" $1).*%${1}=${2}%;"
        shift 2
done
sed -e "$cmd" conf.file > test.tmp

it was more efficient, more intelligent and it works :)
(from comp.unix.shell)