Added tTrimL, tTrimR, and tCheckPackages

towel.sh

@@ -24,6 +24,36 @@
 #
 
 
+#
+#   Checks to see if listed packages have been installed.
+#   Currently DEB packages only.
+#
+# Parameters:
+#
+#   RESULT - Variable in which to return the packages that are missing.
+#   VAR    - List of packages to check, sparated by spaces.
+#
+function tCheckPackages() {
+	local __RESULT=$1
+	local __PACKAGES=${*:2}
+	local __MISSING=
+	local __P=
+
+	set +e
+	for __P in ${__PACKAGES}; do
+		dpkg-query -s ${__P} 2> /dev/null | grep -q ^"Status: install ok installed"$
+		if [ "$?x" == "1x" ]; then
+			__MISSING="${__MISSING} ${__P}"
+		fi
+	done
+	set -e
+
+	tTrimL __MISSING "${__MISSING}"
+
+	eval $__RESULT=\${__MISSING}
+}
+
+
 #
 #   Escapes a given string so it's safe to write into an XML document.
 #
@@ -214,10 +244,49 @@ function tTrim() {
 }
 
 
+#
+#   Removes whitespace from the beginning of a string.
+#
+# Parameters:
+#
+#   RESULT - Variable in which to return the trimmed string.
+#   VAR    - String to trim.
+#
+function tTrimL() {
+	local __RESULT=$1
+	local __VAR="${*:2}"
+
+	# remove leading whitespace characters
+	__VAR="${__VAR#"${__VAR%%[![:space:]]*}"}"
+
+	eval $__RESULT=\${__VAR}
+}
+
+
+#
+#   Removes whitespace from the end of a string.
+#
+# Parameters:
+#
+#   RESULT - Variable in which to return the trimmed string.
+#   VAR    - String to trim.
+#
+function tTrimR() {
+	local __RESULT=$1
+	local __VAR="${*:2}"
+
+	# remove trailing whitespace characters
+	__VAR="${__VAR%"${__VAR##*[![:space:]]}"}"
+
+	eval $__RESULT=\${__VAR}
+}
+
+
 #
 # We're a library.  Don't run us.
 #
 if [ -z "${BASH_SOURCE[1]}" ]; then
 	echo "This is a library.  Include it into other scripts.  Don't execute it."
+	echo "Visit https://skunkworks.kangaroopunch.com/skunkworks/towel for more."
 	exit 0
 fi