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#!/bin/bash
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# Expands bash-style {} expressions.
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# See <http://www.gnu.org/software/bash/manual/bash.html#Brace-Expansion>.
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# Filters each line from stdin to stdout.
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# Warning: Due to shell limitations, a blank line will be interpreted as EOF.
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sedEreFlag="$(test "$(uname)" = Darwin && echo E || echo r)"
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8
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sed () { "$(which sed)" -"$sedEreFlag" "$@";}
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10
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echoEach () { local line; for line in "$@"; do echo "$line"; done; }
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12
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singleQuote="'"
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singleQuoteEsc="'\''"
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CR=$'\r'
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LF=$'\n'
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braceKeep='./{'
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bracketKeep='{*[*,*]*}'
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while true; do
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read # get next line from stdin; strips trailing newlines
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line="$REPLY"
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test -z "$line" && break # EOF if no line or empty line
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if test "${line/$braceKeep/}" != "$line" \
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-o "${line/$bracketKeep/}" != "$line"; then # line contains unparseable exprs
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echo "$line" # don't expand
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else
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line="${line//$CR/}" # remove \r
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line="${line//$singleQuote/$singleQuoteEsc}" # escape single quotes
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line="$(echo "$line"|sed -e "s/[^{,}]+/'&'/g")" # escape non-brace chars
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eval echoEach $line # brace-expand $line
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fi
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done
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