./script.sh: line 3: [: dna_input.txt: integer expression expected

#!/bin/bash                                                                                                                      
#check to see if there is an input file:                                                                                         
if [ $1 -lt 1 ]
then
  echo "Usage: $0 file ..."
  exit 1
fi

#Check if the file is empty or not                                                                                               
file=$1
if [[ -s $1 ]]
then
  echo ""
  echo "**** $file has data."
  echo "Number of non-empty lines:"
  grep -cve '^\s*$' $file
  echo "Mumber of empty lines:"
  grep -ce '^\s*$' $file
  #grep -cvP '^\s*$' $file -- above line originally was like this one                                                            
  echo ""
  cat $1 | sed 's/>/\n>/g' > temp1.txt
  cat temp1.txt | sed '/^>/ d' > temp2.txt
  #Remove duplicate empty lines:                                                                                                 
  awk '!NF{if(++n <=1) print; next}; {n=0; print}' < temp2.txt > DNA.out
  echo ""
  #convert to mRNA and remove temp1, temp2 to avoid confusion                                                                    
  tr ACGT UGCA < DNA.out > RNA.out
  rm temp1.txt temp2.txt

else
  echo "**** $1 has no data, or file does not exist."
  echo "**** done!"
  echo ""
fi;

#!/bin/sh                                                                                                                        
while read rna;do
  aawork=$(echo "${rna}" |sed -n -e 's/\(...\)/\1 /gp' | sed -f rna.sed)
  echo "$aawork" | sed 's/ //g'
  echo "$aawork" | tr ' ' '\012' | sort | sed '/^$/d' | uniq -c | sed 's/[ ]*\([0-9]*\) \(.*\)/\2: \1/'
done

./conversion.sh < RNA.out

s/UUU /Phe /g
s/UUC /Phe /g
s/UUA /Leu /g
s/UUG /Leu /g
s/UCU /Ser /g
s/UCC /Ser /g
s/UCA /Ser /g
s/UCG /Ser /g
s/UAU /Tyr /g
s/UAC /Tyr /g
s/UAA /STOP /g
s/UAG /STOP /g
s/UGU /Cys /g
s/UGC /Cys /g
s/UGA /STOP /g
s/UGG /Trp /g
s/CUU /Leu /g
s/CUC /Leu /g
s/CUA /Leu /g
s/CUG /Leu /g
s/CCU /Pro /g
s/CCC /Pro /g
s/CCA /Pro /g
s/CCG /Pro /g
s/CAU /His /g
s/CAC /His /g
s/CAA /Gln /g
s/CAG /Gln /g
s/CGU /Arg /g
s/CGC /Arg /g
s/CGA /Arg /g
s/CGG /Arg /g
s/AUU /Ile /g
s/AUC /Ile /g
s/AUA /Ile /g
s/AUG /Met /g
s/ACU /Thr /g
s/ACC /Thr /g
s/ACA /The /g
s/ACG /Thr /g
s/AAU /Asn /g
s/AAC /Asn /g
s/AAA /Lys /g
s/AAG /Lys /g
s/AGU /Ser /g
s/AGC /Ser /g
s/AGA /Arg /g
s/AGG /Arg /g
s/GUU /Val /g
s/GUC /Val /g
s/GUA /Val /g
s/GUG /Val /g
s/GCU /Ala /g
s/GCC /Ala /g
s/GCA /Ala /g
s/GCG /Ala /g
s/GAU /Asp /g
s/GAC /Asp /g
s/GAA /Glu /g
s/GAG /Glu /g
s/GGU /Gly /g
s/GGC /Gly /g
s/GGA /Gly /g
s/GGG /Gly /g

>Header_Sequence_1
GTACGACGGAGTGTTATAAGATGGGAAATCGGATACCAGATGAAATTGTGGATCGGTGCAAAA
GTCGGCAGATATCGTTGAAGTCATAGGTGATTATGTTCAATTAAAGAAGCAAGGCCGAAACTAC
TTTGGACTCTGTCCTTTTCATGGAGAAAGCACACCTTCGTTTTCCGTATCGCCCGACAAACAGAT
TTTTCATTGCTTTGGCTGCGGAGCGGGCGGCAATGTTTTCTCTTTTTTAAGGCAGATGGAAGGCT
ATTCTTTTGCCGAGTCGGTTTCTCACCTTGCTGACAAATACCAAATTGATTTTCCAGATGATATAA
CAGTCCATTCCGGAGCCCGGCCAGAG

>Header_Sequence_2
TCTTCTGGAGAACAAAAAATGGCTGAGGCACATGAGCTCCTGAAGAAATTTTACCATCATTTGT
TAATAAATACAAAAGAAGGTCAAGAGGCACTGGATTATCTGCTTTCTAGGGGCTTTACGAAAGA
GCTGATTAATGAATTTCAGATTGGCTATGCTCTTGATTCTTGGGACTTTATCACGAAATTCCTTGT
AAAGAGGGGATTTAGTGAGGCGCAAATGGAAAAAGCGGGTCTCCTGATCAGACGCGAAGACGGAAGCGGATATTTCGACCGCTTCAGAAACC
GTGTCATGTTTCCGATCCATGATCATCACGGGGCTGTTGTTGCTTTCTCAGGCAGGGCTCTTGG

>Header_Sequence_3
CCGCTGTATTCTCAGCCAAGCGGTATAGTCTCCGCTGTATTCTCAGCCCCAGCCGTTCCACTCAG
AGGAACTTTAAAGGATGTTCCTGTTGAGGGCTCATCATCGTCATCGTCATCATCATCATCATCAT
CATCATCATCATCATCAACATCAACCGTCGCACCAGCAAATAAGGCAAGAACTGGAGAAGACGC
AGAAGGCAGTCAAGATTCTAGTGGTACTGAAGCTTCTGGTAGCCAGGGTTCTGAAGAGGAAGG
TAGTGAAGACGATGGCCAAACTAGTGCTGCTTCCCAACCCACTACTCCAGCTCAAAGTGAAGGC
GCAACTACCGAAACCATAGAAGCTACTCCAAAAGAAGAATGCGGCACTTCATTTGTAATGTGGT
TCGGAGAAGGTACCCCAGCTGCGACATTGAAGTGTGGTGCCTACACTATCGTCTATGCACCTAT
AAAAGACCAAACAGATCCCGCACCAAGATATATCTCTGGTGAAGTTACATCTGTAACCTTTGAA
AAGAGTGATAATACAGTTAAAATCAAGGTTAACGGTCAGGATTTCAGCACTCTCTCTGCTAATTC
AAGTAGTCCAACTGAAAATGGCGGATCTGCGGGTCAGGCTTCATCAAGATCAAGAAGATCACT
CTCAGAGGAAACCAGTGAAGCTGCTGCAACCGTCGATTTGTTTGCCTTTACCCTTGATGGTGGT
AAAAGAATTGAAGTGGCTGTACCAAACGTCGAAGATGCATCTAAAAGAGACAAGTACAGTTTG
GTTGCAGACGATAAACCTTTCTATACCGGCGCAAACAGCGGCACTACCAATGGTGTCTACAGGT
TGAATGAGAACGGAGACTTGGTTGATAAGGACAACACAGT

./script.sh input.txt

./conversion.sh < RNA.out