diff --git a/src/common.cpp b/src/common.cpp
index d097f5844..73e2f43ae 100644
--- a/src/common.cpp
+++ b/src/common.cpp
@@ -78,7 +78,6 @@ const wchar_t *program_name;
 int debug_level = 1;         // default maximum debug output level (errors and warnings)
 int debug_stack_frames = 0;  // default number of stack frames to show on debug() calls
 
-
 /// Be able to restore the term's foreground process group.
 /// This is set during startup and not modified after.
 static pid_t initial_fg_process_group = -1;
@@ -93,24 +92,6 @@ static volatile bool termsize_valid = false;
 static char *wcs2str_internal(const wchar_t *in, char *out);
 static void debug_shared(const wchar_t msg_level, const wcstring &msg);
 
-bool is_whitespace(wchar_t c) {
-    switch (c) {
-        case ' ':
-        case '\t':
-        case '\r':
-        case '\n':
-        case '\v':
-            return true;
-        default:
-            return false;
-    }
-}
-
-bool is_whitespace(const wcstring &input) {
-    bool (*pred)(wchar_t c) = is_whitespace;
-    return std::all_of(input.begin(), input.end(), pred);
-}
-
 #if defined(OS_IS_CYGWIN) || defined(WSL)
 // MS Windows tty devices do not currently have either a read or write timestamp. Those
 // respective fields of `struct stat` are always the current time. Which means we can't
diff --git a/src/common.h b/src/common.h
index cf6963349..98785ab24 100644
--- a/src/common.h
+++ b/src/common.h
@@ -217,14 +217,6 @@ extern const wchar_t *program_name;
 /// Set to false if it's been determined we can't trust the last modified timestamp on the tty.
 extern const bool has_working_tty_timestamps;
 
-/// A list of all whitespace characters
-extern const wcstring whitespace;
-extern const char *whitespace_narrow;
-
-bool is_whitespace(const wchar_t input);
-bool is_whitespace(const wcstring &input);
-inline bool is_whitespace(const wchar_t *input) { return is_whitespace(wcstring(input)); }
-
 /// This macro is used to check that an argument is true. It is a bit like a non-fatal form of
 /// assert. Instead of exiting on failure, the current function is ended at once. The second
 /// parameter is the return value of the current function on failure.