Batch deleting files in Windows

List all the jpg files:

dir /s *.jpg /b > jpgs.txt

Delete all the jpg files:

del /s /q /f /a *.jpg

Yum show every available version of a package

yum --showduplicates list [package]

Should be called --all-versions instead.

Get unique values from an array in Perl

# Unique an array

@unique_list = keys %{{ map { $_ => 1 } @big_list }}; # aka dedupe a list

# Unique a hash on a specified key 'id'

@unique_list = values %{{ map { $_->{id} => $_ } %big_hash }};

Explanation

Dedupe lines in place

in vim, select a list of values with shift-V (visual mode), and then type :sort u to sort them and remove duplicates.

XSL de-duping

example:

<xsl:choose> <xsl:when test="/session/dataset = 'news'"> <xsl:for-each-group select="item" by="lower-case(title)"> <xsl:apply-templates select="current-group()[1]"> </xsl:apply-templates></xsl:for-each-group> </xsl:when> <xsl:otherwise> <xsl:apply-templates select="item[title != '']"> </xsl:apply-templates></xsl:otherwise>
</xsl:choose>