Shell Programming and Scripting

#!/bin/sh 
filemerge=/path/merge 
newfile=/path/abc_def_xxx.txt. 
# 
ls /path/directory/ | grep abc_def* > $filemerge 
# 
for j in `cat $filemerge` 
do 
cat $j >> $newfile 
echo "adding $filemerge to $newfile"
rm $j
done 
rm $filemerge

#!/bin/sh 
filemerge=/path/merge # this is an arbitrary file that you are using. Just make up a path and filename
newfile=/path/abc_def_xxx.txt   #This is the new file that you want everything in 
# 
ls /path/directory/ | grep abc_def* > $filemerge     #this is doing an ls and putting all of the filenames 
                                                     #into a file that you will run through
# 
for j in `cat $filemerge`           #This is reading the file one line at a time and doing the following: 
do 
cat $j >> $newfile                  #adding info to newfile...note that it is appending everything to it
echo "adding $filemerge to $newfile"   #just letting you know where it is in process
rm $j                       #deleting old file
done 
rm $filemerge     #deleting file that had list of all filenames

pat=$1 
suffix=${pat##*.} 
first=${pat%.*}
for file in ${first}_*_*.${suffix}
do
  last=${file##*_}
  cat "$file" >> "${first}_${last}"
done

cat "$file" >> "${first}_${last}" && rm "$file"

done >> filemerge.log

for f in ${1%.*}_*_*.${1##*.}; do
  cat "$f" >> "${1%.*}_${f##*_}"
done