tweak get_config() so that it only executes one external

binary (sed) instead of chaining multiple ones (trunk r7798)

svn path=/main/branches/2.1.2/; revision=7826

diff --git a/bin/etc-update b/bin/etc-update
index 0b0e3dedef184afe6511db1b08e3ef2f0bbe7fe5..0a6a79e9cc1c41184a4da6b5515dbad9bf82003f 100755 (executable)
--- a/bin/etc-update
+++ b/bin/etc-update
@@ -17,15 +17,21 @@ if type -P gsed >/dev/null ; then
 fi
 
 function get_config() {
-       item=$1
-
-       # First strip off comment lines, then grab the configuration
-       # item. If there's more than one of the same configuration item,
-       # then allow the last setting to take precedence.
-       local result
-       result=$(cut -d'#' -f1-1 ${PORTAGE_CONFIGROOT}etc/etc-update.conf | \
-               sed -ne "s/^ *$item *= *\([\"']\{0,1\}\)\(.*\)\1/\2/p" |sed -e '$p;d')
-       eval echo $result
+       # the sed here does:
+       #  - strip off comments
+       #  - match lines that set item in question
+       #    - delete the "item =" part
+       #    - store the actual value into the hold space
+       #  - on the last line, restore the hold space and print it
+       # If there's more than one of the same configuration item, then
+       # the store to the hold space clobbers previous value so the last
+       # setting takes precedence.
+       local item=$1
+       eval echo $(sed -n \
+               -e 's:[[:space:]]*#.*$::' \
+               -e "/^[[:space:]]*$item[[:space:]]*=/{s:[^=]*=[[:space:]]*\([\"']\{0,1\}\)\(.*\)\1:\2:;h}" \
+               -e '${g;p}' \
+               "${PORTAGE_CONFIGROOT}"etc/etc-update.conf)
 }
 
 function scan() {