diff --git a/md2parallel.sh b/md2parallel.sh
index 3f225a8..34565e1 100755
--- a/md2parallel.sh
+++ b/md2parallel.sh
@@ -23,16 +23,24 @@ KEEP_TMP_FILES=0
 # convert md to html 
 pandoc --wrap=none -f markdown $DIRNAME/${BASENAME}.md -t html -o ${BASENAME}.html 
 # convert html to tex 
-#sed -i '' 's@<p>@\n\\pstart\n@' ${BASENAME}.html
-#sed -i '' 's@</p>@\n\\pend@'    ${BASENAME}.html
-sed -i '' 's@<p>@\n\\pend\\pstart\n@' ${BASENAME}.html
-sed -i '' 's@</p>@@'    ${BASENAME}.html
-sed -i '' 's@“@\\enquote{@g' ${BASENAME}.html
-sed -i '' 's@”@}@g'          ${BASENAME}.html
-sed -i '' 's@<h1.*">@\\section[@' ${BASENAME}.html
-sed -i '' 's@</h1>@]@'           ${BASENAME}.html
-sed -i '' 's@<h2.*">@{@' ${BASENAME}.html
-sed -i '' 's@</h2>@}@'   ${BASENAME}.html
-sed -i '' "s@’@'@g" ${BASENAME}.html
+# check if on linux or macos 
+if [[ $(uname) == "Linux" ]] 
+then 
+    SED_CMD="sed -i" 
+elif [[ $(uname) == "Darwin" ]]
+then
+    SED_CMD="sed -i ''" 
+fi
+#$SED_CMD 's@<p>@\n\\pstart\n@' ${BASENAME}.html
+#$SED_CMD 's@</p>@\n\\pend@'    ${BASENAME}.html
+$SED_CMD 's@<p>@\n\\pend\\pstart\n@' ${BASENAME}.html
+$SED_CMD 's@</p>@@'    ${BASENAME}.html
+$SED_CMD 's@“@\\enquote{@g' ${BASENAME}.html
+$SED_CMD 's@”@}@g'          ${BASENAME}.html
+$SED_CMD 's@<h1.*">@\\section[@' ${BASENAME}.html
+$SED_CMD 's@</h1>@]@'           ${BASENAME}.html
+$SED_CMD 's@<h2.*">@{@' ${BASENAME}.html
+$SED_CMD 's@</h2>@}@'   ${BASENAME}.html
+$SED_CMD "s@’@'@g" ${BASENAME}.html
 mv ${BASENAME}.html ${BASENAME}.tex
 cat ${BASENAME}.tex && rm ${BASENAME}.tex