Script to identify the files based on current date and file name pattern

In your find command you can drop the single-quotes around the date variable as

find  -type f -name "*_${date}*.csv"

since the double-quotes " as such expand the value of variables in bash and you don't have to single quote again.

Demo:-

touch abc_2016-12-28-3523424-acsfsc.csvtouch abc_2016-12-29-3523424-acsfsc.csv

Confirming once the presence of the files without the -name filter

find . -maxdepth 1 -type f -print./abc_2016-12-28-3523424-acsfsc.csv./abc_2016-12-29-3523424-acsfsc.csv

Now setting the variable date to today's date as

date=$(date +%Y-%m-%d)find  -type f -name "*_${date}*.csv"./abc_2016-12-28-3523424-acsfsc.csv

Also do not use pipe-line to set variables in bash, use process-substitution and use -print0 for a more robust handling of files with special characters in the filenames.

while IFS='' read -r -d '' filenamedo    echo "filename : ${filename}"    var=$(base64 "$filename"| perl -pe 's/\n//g');    var1=$(curl -XPUT "http://localhost:9200/documents-$date/document/?pipeline=attachment&pretty" -d '{ "data" : "'"$var"'" }')done < <(find -type f -name "*_${date}*.csv" -print0)