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bug#7068: Feature request: uniq --field-separator="SEP" --consider-field
From: |
Stefan Nowak |
Subject: |
bug#7068: Feature request: uniq --field-separator="SEP" --consider-fields="a, b, c" --ignore-fields="x, y, z" |
Date: |
Sun, 19 Sep 2010 00:44:17 +0200 |
Hello developers!
CURRENT SYNTAX:
http://www.gnu.org/software/coreutils/manual/html_node/uniq-invocation.html
--skip-fields=n Skip n fields on each line before checking for
uniqueness. Use a null string for comparison if a line has fewer than
n fields. Fields are sequences of non-space non-tab characters that
are separated from each other by at least one space or tab.
--- FEATURE REQUEST #1 ---
--field-separator="SEP", -F
EXAMPLE:
Scenario: Imagine a filesystem listing. Because of the hierarchical
nature, all entries are unique. Now I want to ignore the filepath-
prefix (skip the field/s by -F), and only consider the basename, and
see how many instances exist of it, and where (all duplicate instances
by -D).
Input:
folder a<TAB>file 1
folder b<TAB>file 1
folder b<TAB>file 2
folder c<TAB>file 3
Commandline:
cat sample.txt | guniq -D -F "\t" -f 1
Output:
folder a<TAB>file 1
folder b<TAB>file 1
BENEFIT: If you can define the separator character (i.e. TAB), then
you have the freedom to have all other characters besides SEP within
your column data, i.e. your column could then contain SPACE characters.
--- FEATURE SUGGESTION #2 ---
--consider-fields=a[,b,c, ...] Build the comparison string of a line
from these field(s).
--ignore-fields=x[,y,z,...] Build the comparison string of a line
by excluding these field(s).
EXAMPLE:
Input:
folder a<TAB>file 1<TAB>suffixA
folder b<TAB>file 1<TAB>suffixB
folder b<TAB>file 2<TAB>suffixA
folder c<TAB>file 3<TAB>suffixA
Commandline:
cat sample.txt | guniq -D -F "\t" --consider-fields="2"
Equivalent to:
cat sample.txt | guniq -D -F "\t" --ignore-fields="1,3"
Output:
folder a<TAB>file 1<TAB>suffixA
folder b<TAB>file 1<TAB>suffixB
WORKAROUND MEANWHILE: Pre-insert a RegEx find/replace process in the
pipe before uniq, which brings all the comparison-ignored data to the
front, and then --skip-fields.
BENEFIT: Of course it would be much more convenient to work with the
data as-is, and have the functions --consider-fields and --ignore-
fields.
Regards, Stefan Nowak
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- bug#7068: Feature request: uniq --field-separator="SEP" --consider-fields="a, b, c" --ignore-fields="x, y, z",
Stefan Nowak <=