Hi, I have a bash shell script, which is behaving wierd. Sometimes it prints the output as expected, and sometimes it doesn't produce any output at all. Its functionality, in brief is . scan a text file, . pick up lines based on a keyword, and select a specific field from that line . the first entry found, describes what that file is meant for . leave all those fields, which contain unwanted keywords . finally make a unique list of these descriptions The script, most of the times, is giving the intended output, but sometimes not. Try to execute this script, number of times in succession, may be try 10 times...; and obsorve the output. Could anyone kindly let me know, why this script is behaving like this. There may be some other options to do this with 'awk' and 'sed', but I specifically want to know why this is behaving like this. I am enclosing both the text file and the script. Thanks a lot in advance. Regards, Tejo. ---------------- Here are the details of the bash version and OS I am running. > GNU bash, version 2.05b.0(2)-release (sparc-sun-solaris2.5.1) > Copyright (C) 2002 Free Software Foundation, Inc. OS specification: > SunOS tejo 5.6 Generic_105181-33 sun4u sparc SUNW This is how one can invoke the script. bash$ ./getRequiredInfo.sh -o REPORT.DAT mydescr.txt; cat REPORT.DAT # here comes the script BEGIN #! /bin/bash # set -vx; usage_help() { echo "usage: $0 [var2] ... [varN]"; echo echo -e "out-file is:" echo -e "\toutput file, into which the report will be written" echo echo -e "varN is:" echo -e "\tdescription file"; exit 1; } # check if we have write permission validate_outfile() { [ -r $REPORT ] && [ ! -w $REPORT ] && { \ echo "Specified file, $REPORT cannot be written.."; echo "Exiting.."; exit 1; } } noInfo(){ echo "No required information ..."; echo; } # min 3 params required, -0, outfilename and one desciption file [ $# -lt 3 ] && { usage_help; } REPORT= while getopts o: param do case "$param" in o) REPORT="$OPTARG" validate_outfile; ;; [?]) usage_help; exit 1; ;; esac done shift $(($OPTIND - 1)) VAR_LIST=$*; KEYWORD=keyword EXCLUDE='unwanted1 unwanted2 unwanted3' echo | cat > $REPORT; for file in $VAR_LIST do /bin/rm -f .t1; echo "Processing $file ..."; # get the descriptions # remove duplicate descriptions grep $KEYWORD $file | cut -d',' -f4- | \ cut -d'(' -f2 | cut -d')' -f1 | cat > .t1; # detect if no $KEYWORD is not found in the file # and skip the next steps in the loop ! [ -s .t1 ] && { noInfo; continue; } # first entry will be title specification # dump it into the report echo -ne "Title:" | cat >> $REPORT; head -1 .t1 | cat >> $REPORT; # now remove, the first line, as we have already taken care of # it as title specification, and dump remaining lines into temp # file let noOfLines=`wc -l .t1 | awk '{print $1}'`; noOfLines=`expr $noOfLines - 1`; tail -$noOfLines .t1 | tee | cat > .t1; # remove unwanted entries from the output for word in $EXCLUDE do grep -v $word .t1 | tee | cat > .t1; done; # remove duplicates sort -u .t1 | tee | cat > .t1; # dump in the file echo -e "Required descriptions :" | cat >> $REPORT; cat .t1 >> $REPORT; done; /bin/rm -f .t1 .t2; echo echo "Done" # END --here comes the sample text file, which needs to be scanned-- keyword.1 , type1 , accesstype , fixed(Title Specification, description1, description2) keyword.3 , type1 , accesstype , fixed(unwanted1 description) keyword.4 , type1 , accesstype , fixed(description1) keyword.5 , type1 , accesstype , fixed(unwanted1 description) keyword.6 , type1 , accesstype , fixed(unwanted1 description) keyword.7 , type1 , accesstype , fixed(description11) keyword.8 , type1 , accesstype , fixed(description11) keyword.9 , type1 , accesstype , fixed(description12) keyword.10 , type1 , accesstype , fixed(description0) keyword.11 , type1 , accesstype , fixed(unwanted2 description) keyword.12 , type1 , accesstype , fixed(description23) keyword.13 , type1 , accesstype , fixed(description23) keyword.14 , type1 , accesstype , fixed(description24) keyword.15 , type1 , accesstype , fixed(description) keyword.16 , type1 , accesstype , fixed(unwanted3 description) keyword.17 , type1 , accesstype , fixed(description12) keyword.18 , type1 , accesstype , fixed(description123) keyword.19 , type1 , accesstype , fixed(description) keyword.20 , type1 , accesstype , fixed(unwanted3 description) keyword.21 , type1 , accesstype , fixed(description345) keyword.22 , type1 , accesstype , fixed(description456) keyword.23 , type1 , accesstype , fixed(description) keyword.24 , type1 , accesstype , fixed(unwanted2 description) keyword.25 , type1 , accesstype , fixed(description) keyword.26 , type1 , accesstype , fixed(description) keyword.27 , type1 , accesstype , fixed(unwanted1 description) -- text file end--