diff --git a/contrib/dpkg b/contrib/dpkg
index 4cacd4ee..709efc25 100644
--- a/contrib/dpkg
+++ b/contrib/dpkg
@@ -224,7 +224,7 @@ _dpkg_source()
                 "-D")
                     # -D: override or add a .dsc field and value
                     # if $cur doesn't contain a = yet, suggest variable names
-                    if echo -- "$cur" | grep -q "="; then
+                    if [[ "$cur" == *=* ]]; then
                         # $cur contains a "="
                         COMPREPLY=()
                         return 0
diff --git a/contrib/postfix b/contrib/postfix
index e3712aa9..0dfd93b5 100644
--- a/contrib/postfix
+++ b/contrib/postfix
@@ -182,7 +182,7 @@ _postsuper()
         -[dr])
             len=${#cur}
             idx=0
-            for pval in $( echo ALL; mailq 2>/dev/null | \
+            for pval in ALL $( mailq 2>/dev/null | \
                 sed -e '1d; $d; /^[^0-9A-Z]\|^$/d; s/[* !].*$//' ); do
                 if [[ "$cur" == "${pval:0:$len}" ]]; then
                     COMPREPLY[$idx]=$pval
@@ -194,7 +194,7 @@ _postsuper()
         -h)
             len=${#cur}
             idx=0
-            for pval in $( echo ALL; mailq 2>/dev/null | \
+            for pval in ALL $( mailq 2>/dev/null | \
                 sed -e '1d; $d; /^[^0-9A-Z]\|^$/d; s/[* ].*$//; /!$/d' ); do
                 if [[ "$cur" == "${pval:0:$len}" ]]; then
                     COMPREPLY[$idx]=$pval
@@ -206,7 +206,7 @@ _postsuper()
         -H)
             len=${#cur}
             idx=0
-            for pval in $( echo ALL; mailq 2>/dev/null | \
+            for pval in ALL $( mailq 2>/dev/null | \
                 sed -e '1d; $d; /^[^0-9A-Z]\|^$/d; /^[0-9A-Z]*[* ]/d; s/!.*$//' ); do
                 if [[ "$cur" == "${pval:0:$len}" ]]; then
                     COMPREPLY[$idx]=$pval