how to retrieve required specific info from the file

Shell Programming and Scripting
1

Hi
I have a file which consists of a number in the square brackets, followed by the blank line, then several lines which describe this number. This pattern is repeated several thousands time. The number in the brackets and the decription of it is unique. For example:
[2153]

ASRVSERV=1241GD;
BPCONN=avtr213;
OMGEO=FIET

[4324]

ASRVSERV=333TS;
BPCONN=AUTO1243;
OMGEO=TSAM

etc....................

Is there a way to retireve info from the above file for several specific numbers and output it to another file?
I do not keep my hopes high, but may be somebody did similar file manipulations. Thanks a lot for any help or hints -A

PS I am in ksh88

2 
awk  -v RS=    '/\[2153\]|\[4324\]|\[9999\]/ { a=NR }  NR==a, NR==a+1'  ORS="\n\n"   filename  >  output

Add as many numbers as you need to search, with no spaces in between and separated from the pipe | symbol, as shown above.

3

Basically you are trying to parse multi-line record.
See my blog for an example:
Chi Hung Chan: How to Parse Multiline in AWK

Below should do the job

$ cat d.sh
#! /bin/sh

if [ $# -ne 2 ]; then
        echo "Usage: $0 <input> <pattern>"
        exit 1
fi


awk '
BEGIN {
        RS=""
        FS="\n"
}
NR%2==1 && $1 ~ /\['$2'\]/ {
        getline
        print
}' $1

$ cat d.in
[2153]

ASRVSERV=1241GD;
BPCONN=avtr213;
OMGEO=FIET

[4324]

ASRVSERV=333TS;
BPCONN=AUTO1243;
OMGEO=TSAM

[4858]

ASRVSERV=345RE;
BPCONN=ABC123;
OMGEO=MSAM

[8888]

ASRVSERV=899AS;
BPCONN=CAR1234;
OMGEO=IAOS

[8912]

ASRVSERV=728WW;
BPCONN=POP1239;
OMGEO=JKAE

[1211]

ASRVSERV=999UI;
BPCONN=LOC1932;
OMGEO=UISE

$ ./d.sh d.in 4324
ASRVSERV=333TS;
BPCONN=AUTO1243;
OMGEO=TSAM

$ ./d.sh d.in 8912
ASRVSERV=728WW;
BPCONN=POP1239;
OMGEO=JKAE

$ ./d.sh d.in 1111

$