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sed pattern matching question

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# 8  
Old 04-29-2011
I think

Code:
sed -n -e '/^.*ABCD|/p' $fileName | sed -e 's/^.*ABCD|//' | sed -e 's/|ABCD$//' > ${fileName}.tmp

could be written (save 2 sed and 2 pipes)

Code:
sed '/^.*ABCD|/!d;s/^.*ABCD|//;s/|ABCD$//' $fileName > ${fileName}.tmp

Last edited by ctsgnb; 04-29-2011 at 11:29 AM..
# 9  
Old 04-29-2011
Quote:
I have yet to actually find any records that begin with .*ABCD| or end with |ABCD
The filter operates on lines that contain 'ABCD|' anywhere in the line. Use grep to find them.
Quote:
One other thing that is confusing me is that the pattern before the print matches the one after the print. The only difference seems to be that the first is being fed to print, while the second occurrence is being targeted for removal. I'm am not quite sure what the developer's intent was there.
The first sed command filters out only lines that contain 'ABCD|' and passes them on unchanged, while the second sed command takes that line and does a substitution -- cleans up the beginning of line until 'ABCD|', including.

Quote:
As for sed itself, would it be safe to say that the result of this specific command would be that any entire line which either begins with any one or more characters followed by a literal ABCD and a | would be removed.
It depends on the contents of the line. It may be all removed, or not.
If the line ends with 'ABCD|', it's gonna get all removed by the second sed command.

Quote:
And any line ending with a pipe followed by a literal ABCD and end of line would be removed?
Only the trailing '|ABCD' is removed.
This User Gave Thanks to mirni For This Post:
topmhat
# 10  
Old 04-29-2011
Thank you everyone!
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