how to remove carriage return line feed from file in unix

#cat test_C
hi
my name is arpit
this is test for cr lf
reg
arpit
#od -c test_C
0000000 h i \n m y n a m e i s a r
0000020 p i t \n t h i s i s t e s t
0000040 f o r c r l f \n r e g \n a
0000060 r p i t \n
0000065

#od -b test_C
0000000 150 151 012 155 171 040 156 141 155 145 040 151 163 040 141 162
0000020 160 151 164 012 164 150 151 163 040 151 163 040 164 145 163 164
0000040 040 146 157 162 040 143 162 040 154 146 012 162 145 147 012 141
0000060 162 160 151 164 012
0000065

#cat test_C tr -d "\015\012" > op
#cat op
himy name is arpitthis is test for cr lfregarpit#
#
--tr command with -d option deletes char specified.
#od -b op
0000000 150 151 155 171 040 156 141 155 145 040 151 163 040 141 162 160
0000020 151 164 164 150 151 163 040 151 163 040 164 145 163 164 040 146
0000040 157 162 040 143 162 040 154 146 162 145 147 141 162 160 151 164
0000060

#od -c op
0000000 h i m y n a m e i s a r p
0000020 i t t h i s i s t e s t f
0000040 o r c r l f r e g a r p i t
0000060
#