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Matching blank lines

By jdogg ·
I am trying to match all blank (including null) lines in a text file. Using sed the regular expression is:

/^[<SPACE><TAB>]*$/

which should match 0 or more occurrences of a space or tab followed by the end of line. I have even seen this expression quoted - a colleague has used the same expression in an ex command in vi and both of us cannot get it to work.

Any ideas?

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Matching blank lines

by Point Man In reply to Matching blank lines

Possibly within vi your friend was including the final '/' which shouldn't be included. This works for me under vi:

/$[<space><tab>]*$

Where the space is pressing your space character and the tab is pressing the tab character.

grep -c '^[ ]*$' ./httpd.conf

Where the whitespace is pressing the space and tab characters.

Does this help?

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Matching blank lines

by jdogg In reply to Matching blank lines

All patterns must be surrounded by slashes

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Matching blank lines

by argv[0] In reply to Matching blank lines

[:space:]*$
be better because of all whitespaces (' ', '\t' and '\r') will be matched.
It's impotent especially if your text coming from DOS/Windows

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Matching blank lines

by jdogg In reply to Matching blank lines

Fair play - the POSIX classes work

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Matching blank lines

by jdogg In reply to Matching blank lines

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