diff --git a/sh/document b/sh/document
index 3c3d0c1..121494a 100755
--- a/sh/document
+++ b/sh/document
@@ -28,7 +28,7 @@ document2() {
         @-*)
             s="$code"
             n="${s%%[!a-zA-Z0-9_-]*}" # substr first word (might not be one)
-            while [ -z "$n" -o "$n" = function -o "$n" = alias ]; do
+            while [ -z "$n" ] || ["$n" = function ] || [ "$n" = alias ]; do
                 [ -n "$s" ] || break
                 s="${s#${s%%[!a-zA-Z0-9_-]*}}" # lstrip to end of word
                 s="${s#*[!a-zA-Z0-9_-]}" # lstrip to next word
@@ -79,7 +79,7 @@ document2() {
         fi
 
         if [ "$s" != ' ' ]; then # don't bother unless it was set to something
-            if [ -z "$n" -o -n "$s" ]; then # might only be a name, check that
+            if [ -z "$n" ] || [ -n "$s" ]; then # might only be a name, check that
                 # just pass the remaining comment through:
                 if [ $o = 1 ]; then
                     # ensure one-liners are their in their own paragraph.
diff --git a/sh/maybesudo b/sh/maybesudo
index 557a5cf..253b713 100755
--- a/sh/maybesudo
+++ b/sh/maybesudo
@@ -44,7 +44,7 @@ maybesudo_() ( ### @-
 
         C|U|b|g|i|l|r|s|t)
         # C: close from (fd)
-        # U: other user (in conjunction wiht -l)
+        # U: other user (in conjunction with -l)
         # b: background
         # g: group
         # i: simulate initial login (TODO)
@@ -57,7 +57,7 @@ maybesudo_() ( ### @-
             ;;
 
         u)      # user
-            if [ -z "$USER" -o "$OPTARG" != "$USER" ]; then
+            if [ -z "$USER" ] || [ "$OPTARG" != "$USER" ]; then
                 note 'maybesudo: users other than yourself are unsupported!'
                 return 1
             fi
diff --git a/sh/stfu b/sh/stfu
index eb102ef..c235d29 100755
--- a/sh/stfu
+++ b/sh/stfu
@@ -68,7 +68,7 @@ stfu() { ### @-
 
     mkdir -p "$temp" || { printf "%s\n" "$0: failed to create temp directory" >&2; return 1; }
 
-    while [ -e "$temp/out_$time" -o -e "$temp/err_$time" ]; do time=$((time+1)); done
+    while [ -e "$temp/out_$time" ] || [ -e "$temp/err_$time" ]; do time=$((time+1)); done
     local out="$temp/out_$time"
     local err="$temp/err_$time"