3 Anchored the match to the beginning of the line
source | link

With your input data, you can try:

$ sed '/Products^Products/d' file 
Number, month, year, reference, store
1,1,2014,13322,main
2,2,2014,13322,main
3,3,2011,1322,main
4,4,2012,3322,main
5,4,2013,122,secondary
12,411,2010,122,Albany
25,41,2009,122,Dallas
35,24,2008,122,New

Using sed -i.bak to edit the file inplace and create a backup file:

sed -i.bak '/Products^Products/d' file

With your input data, you can try:

$ sed '/Products/d' file 
Number, month, year, reference, store
1,1,2014,13322,main
2,2,2014,13322,main
3,3,2011,1322,main
4,4,2012,3322,main
5,4,2013,122,secondary
12,411,2010,122,Albany
25,41,2009,122,Dallas
35,24,2008,122,New

Using sed -i.bak to edit the file inplace and create a backup file:

sed -i.bak '/Products/d' file

With your input data, you can try:

$ sed '/^Products/d' file 
Number, month, year, reference, store
1,1,2014,13322,main
2,2,2014,13322,main
3,3,2011,1322,main
4,4,2012,3322,main
5,4,2013,122,secondary
12,411,2010,122,Albany
25,41,2009,122,Dallas
35,24,2008,122,New

Using sed -i.bak to edit the file inplace and create a backup file:

sed -i.bak '/^Products/d' file
2 added 1 character in body
source | link

With your input data, you can try:

$ sed '/Products/d' file 
Number, month, year, reference, store
1,1,2014,13322,main
2,2,2014,13322,main
3,3,2011,1322,main
4,4,2012,3322,main
5,4,2013,122,secondary
12,411,2010,122,Albany
25,41,2009,122,Dallas
35,24,2008,122,New

Using sed -i.bak to edit the file inplace and create a backup file:

sed -i.bak '/ProductProducts/d' file

With your input data, you can try:

$ sed '/Products/d' file 
Number, month, year, reference, store
1,1,2014,13322,main
2,2,2014,13322,main
3,3,2011,1322,main
4,4,2012,3322,main
5,4,2013,122,secondary
12,411,2010,122,Albany
25,41,2009,122,Dallas
35,24,2008,122,New

Using sed -i.bak to edit the file inplace and create a backup file:

sed -i.bak '/Product/d' file

With your input data, you can try:

$ sed '/Products/d' file 
Number, month, year, reference, store
1,1,2014,13322,main
2,2,2014,13322,main
3,3,2011,1322,main
4,4,2012,3322,main
5,4,2013,122,secondary
12,411,2010,122,Albany
25,41,2009,122,Dallas
35,24,2008,122,New

Using sed -i.bak to edit the file inplace and create a backup file:

sed -i.bak '/Products/d' file
1
source | link

With your input data, you can try:

$ sed '/Products/d' file 
Number, month, year, reference, store
1,1,2014,13322,main
2,2,2014,13322,main
3,3,2011,1322,main
4,4,2012,3322,main
5,4,2013,122,secondary
12,411,2010,122,Albany
25,41,2009,122,Dallas
35,24,2008,122,New

Using sed -i.bak to edit the file inplace and create a backup file:

sed -i.bak '/Product/d' file