Replace between character and white space using unix sed

Question

[dllopezr]

Hi everyone

I have a file like this

>NC_003037.1:453555-454448 Sinorhizobium meliloti 1021 plasmid pSymA, complete sequence
>NC_007493.2:2279220-2278345 Rhodobacter sphaeroides 2.4.1 chromosome 1, complete sequence
>NC_007952.1:1763831-1762950 Paraburkholderia xenovorans LB400 chromosome 2, complete sequence
>NC_005791.1:844089-844916 Methanococcus maripaludis strain S2, complete sequence

that I replace the first two sections to obtain this:

>NC_003037.1:ChrStart-454448 Sinorhizobium meliloti 1021 plasmid pSymA, complete sequence
>NC_007493.2:ChrStart-2278345 Rhodobacter sphaeroides 2.4.1 chromosome 1, complete sequence
>NC_007952.1:ChrStart-1762950 Paraburkholderia xenovorans LB400 chromosome 2, complete sequence
>NC_005791.1:ChrStart-844916 Methanococcus maripaludis strain S2, complete sequence

I've tried to replace the numbers between the "-" and the space before the species name with the word "ChrStop". I've tried sed with [[:blank:]] [[:space:]] and /s options in this way:

sed -i 's/-.*[[:blank:]]/-ChrStop[[:blank:]]/g' filetxt

But always the command replace beyond I want, for example:

>NC_003037.1:ChrStart-ChrStop[[:blank:]]sequence
>NC_007493.2:ChrStart-ChrStop[[:blank:]]sequence
>NC_007952.1:ChrStart-ChrStop[[:blank:]]sequence
>NC_005791.1:ChrStart-ChrStop[[:blank:]]sequence

Can you help me with the correct way to match the space and replace between this character and "-"?

thank you so much.

Answer 1

[Kevin Blighe]

Try this (?):

sed 's/ChrStart\-[0-9]*[[:blank:]]/ChrStart\-ChrStop /g' test
>NC_003037.1:ChrStart-ChrStop Sinorhizobium meliloti 1021 plasmid pSymA, complete sequence
>NC_007493.2:ChrStart-ChrStop Rhodobacter sphaeroides 2.4.1 chromosome 1, complete sequence
>NC_007952.1:ChrStart-ChrStop Paraburkholderia xenovorans LB400 chromosome 2, complete sequence
>NC_005791.1:ChrStart-ChrStop Methanococcus maripaludis strain S2, complete sequence

[dllopezr]

Hi @Kevin, thank you for your help!

If you don't mind, could you explain to me how this command works, especially this part ChrStart\-[0-9]*[[:blank:]]?

What I really want to do is to pass this numbers to different variables, say "ChrStart" = $1 and ChrStop = $2 to pass to another command. The use of "ChrStart" in the above code will spoil this objective?

[Ram]

ChrStart is taken literally
\- is taken as a hyphen (-). The backslash escapes its metacharacter behavior (not required here as - is a metacharacter only within character classes but better safe than sorry.
[0-9]* matches any length of numbers between 0 and 9
[[:blank:]] matches a blank space

ChrStart-100000 is thus broken into 4 matches like so:

|ChrStart|-|100000| |
|----1---|2|--3---|4|