Can SED change 1st & last line? 1

[marrow]

Need to read/alter first line & last line and keep all other lines as is. Can I do so without writing to a temp file more than once. I need to keep original file so will need a newfile for changes. Where line1 = needs a small change to it's date and line2 needs it's record count modified.

Any advice appreciated.

 

[feherke]

Hi

Yes. Or no. This will change the first line to string "first" and the last line to "last", but will create a new file.

sed -i '1s/.*/first/;$s/.*/last/' /path/to/file

Feherke.

http://rootshell.be/~feherke/

 

[marrow]

Thanks Feherke, not sure I made it very clear:

1) FileA contains record1 and 2 fields :
20060215|data
sed will only alter the date field 20060215 in FileA and move to FileB, field2 "data" unchanged

2) all other lines/records to be left as is and copied to FileB

3) FileA - record at end of file :
00|005600
again i would use sed to alter in this case field2 "0056600" in FileA and move to FileB. Field 1 unchanged

So I would like to to create FileB with a new 1st & last record and all other data unchanged, but I only want to use FileA and FileB in the operation, no intermediate temp files to be used.

Many Thanks - Marrow

 

[feherke]

Hi

Ok, and what is wrong ?

[blue]master #[/blue] cat fileA
20060215|data
bla|bla
bla|bla|bla
00|005600
[blue]master #[/blue] sed '1s/.*|/alteredfield|/;$s/|.*/|alteredfield/' fileA > fileB
[blue]master #[/blue] cat fileB
alteredfield|data
bla|bla
bla|bla|bla
00|alteredfield

Feherke.

http://rootshell.be/~feherke/

 

[marrow]

Apogolies Feherke, I misread your reply! Will test..

Thanks Again - Marrow

 

[feherke]

Hi

No problem. I think I misread your question too. The part with keeping the original file I interpreted as making changes in the original file instead of in a copy.

Feherke.

http://rootshell.be/~feherke/

 

[marrow]

All working - Many Thanks

sed "1s/.*00|20060221/00|20060220/;\$s/.*99|$RECORD/99|$NEWRECORD/" FILEIN>>FILEOUT