shell - Replacing pattern with pattern+incrementing number -

here snippet of text files want edit:

"> record:w7_s7_l001_r2_001_43549049:wang1141_nem_0425_6 aggctcgaacttcctttggatgaactccaaaagtccctctaagaagttaacaccttacaa  "> record:w41_s41_l001_r2_001_36873913:wang1141_nem_0425_6 tgcctcaaacttccgtggattaaacatccacagtccctctaagaagttagccgtcaaccaa  "> record:w32_s56_l001_r2_001_29095773:wang1141_nem_0425_6 tgcctcaaacttccttatgcttgcacataaagtccctctaagaagttagactccctattta 

now want replace every ">" ">$a" , incrementing "$a++". found solution worked:

>awk '/>/{sub(/start/,++n);{print}' 

but replaces > number without >.

i appreciate every help!

it's hard believe glance @ man page , maybe quick google couldn't figure out how fix code snippet had found want here is:

$ awk '/>/{sub(/>/,">"++n)}{print}' file ">1 record:w7_s7_l001_r2_001_43549049:wang1141_nem_0425_6 aggctcgaacttcctttggatgaactccaaaagtccctctaagaagttaacaccttacaa  ">2 record:w41_s41_l001_r2_001_36873913:wang1141_nem_0425_6 tgcctcaaacttccgtggattaaacatccacagtccctctaagaagttagccgtcaaccaa  ">3 record:w32_s56_l001_r2_001_29095773:wang1141_nem_0425_6 tgcctcaaacttccttatgcttgcacataaagtccctctaagaagttagactccctattta 

get book effective awk programming, 4th edition, arnold robbins.