Shell Programming and Scripting

True. Re-reading the thread-O/Ps goal description i have to admit it is not at all clear what he really wants and i might have misunderstood him.


For sed, I would suggest the following, which is resilient to trailing spaces in the first field:

Code:

sed 's/ *|/|/2'

[/quote]

hmm, it will change the second instance of trailing blanks in any field, not the trailing blanks in the second field, no?

I suggest the following, revised regexp, which will only change trailing blanks and only so in the second field:

Code:

sed 's/^\([^|]*|[^<spc><tab>]\)[<spc><tab>]*|/\1|/' /path/to/input

Arguably one of the most fire-proof regexps i have ever written. ;-))

bakunin

No. It will remove trailing spaces (if present) only in the second field. The first field will always match, since the spaces are optional (there is only one space in my regular expression). The second match will always be the second field.


I believe you omitted a * quantifier, otherwise your re will only match a second field with a single non-blank followed by blanks. But including the * could lead to a problem with greediness spilling over into subsequent fields if the second field has no blanks. The first [^<spc><tab>] should be [^|]. Regardless, it will fail to remove trailing blanks if there is an embedded blank.

If trailing spaces in the second field need to be deleted, I believe my suggestion is both accurate and robust.

Regards,
Alister

You know what? You are right. Upon taking a nights sleep and a fresh look i come to the conclusion your solution is more robust than mine.

Most of my colleagues start having something else to do when i say "sed", so i enjoy to be able to discuss regexps for a change.

bakunin