bash - sed copy substring from fixed position and copy it in front of line -

i'm dealing many csv files , can't find way sed select substring @ fixed position (chars 9-16) , copy @ beginning of line.

this have:

abc09638006924340017;some_text;some_other_text

this need:

00692434;abc09638006924340017;some_text;some_other_text

the following code in sed gives substring need (00692434) overwrites whole line:

sed 's/^.{8}(.{8}).*/\1/')

i'm using sed "clean" linestrings , inserting variables, called in bash script @ end imports data in postgres. why prefer remain within sed, hint appreciated i'm not real expert.

you need escape curly braces (\{\}) parentheses (\(\)) , append original string (&) in replacement:

text="abc09638006924340017;some_text;some_other_text" echo $text | sed "s/^.\{8\}\(.\{8\}\).*/\1;&/" 

output:

00692434;abc09638006924340017;some_text;some_other_text 

since want extract fixed-length substring @ fixed position, bash-builtins:

text="abc09638006924340017;some_text;some_other_text" echo "${text:8:8};$text"