diff --git a/src/libutil/include/nix/util/file-descriptor.hh b/src/libutil/include/nix/util/file-descriptor.hh
index da12deb12ef..fcb70c7a989 100644
--- a/src/libutil/include/nix/util/file-descriptor.hh
+++ b/src/libutil/include/nix/util/file-descriptor.hh
@@ -104,10 +104,11 @@ void writeFull(Descriptor fd, std::string_view s, bool allowInterrupts = true);
  *
  * @param fd The file descriptor to read from
  * @param eofOk If true, return an unterminated line if EOF is reached. (e.g. the empty string)
+ * @param terminator The chartacter that ends the line
  *
  * @return A line of text ending in `\n`, or a string without `\n` if `eofOk` is true and EOF is reached.
  */
-std::string readLine(Descriptor fd, bool eofOk = false);
+std::string readLine(Descriptor fd, bool eofOk = false, char terminator = '\n');
 
 /**
  * Write a line to a file descriptor.
diff --git a/src/libutil/include/nix/util/serialise.hh b/src/libutil/include/nix/util/serialise.hh
index e1b5e220fee..916fa9ad32a 100644
--- a/src/libutil/include/nix/util/serialise.hh
+++ b/src/libutil/include/nix/util/serialise.hh
@@ -121,7 +121,7 @@ struct BufferedSource : virtual Source
 
     size_t read(char * data, size_t len) override;
 
-    std::string readLine(bool eofOk = false);
+    std::string readLine(bool eofOk = false, char terminator = '\n');
 
     /**
      * Return true if the buffer is not empty.
diff --git a/src/libutil/serialise.cc b/src/libutil/serialise.cc
index b1ec76f32d5..34fafa4ad03 100644
--- a/src/libutil/serialise.cc
+++ b/src/libutil/serialise.cc
@@ -138,7 +138,7 @@ size_t BufferedSource::read(char * data, size_t len)
     return n;
 }
 
-std::string BufferedSource::readLine(bool eofOk)
+std::string BufferedSource::readLine(bool eofOk, char terminator)
 {
     if (!buffer)
         buffer = std::make_unique_for_overwrite<char[]>(bufSize);
@@ -148,7 +148,7 @@ std::string BufferedSource::readLine(bool eofOk)
         if (bufPosOut < bufPosIn) {
             auto * start = buffer.get() + bufPosOut;
             auto * end = buffer.get() + bufPosIn;
-            if (auto * newline = static_cast<char *>(memchr(start, '\n', end - start))) {
+            if (auto * newline = static_cast<char *>(memchr(start, terminator, end - start))) {
                 line.append(start, newline - start);
                 bufPosOut = (newline - buffer.get()) + 1;
                 if (bufPosOut == bufPosIn)
diff --git a/src/libutil/unix/file-descriptor.cc b/src/libutil/unix/file-descriptor.cc
index cbb4903eab9..c71a6845e3a 100644
--- a/src/libutil/unix/file-descriptor.cc
+++ b/src/libutil/unix/file-descriptor.cc
@@ -98,7 +98,7 @@ void writeFull(int fd, std::string_view s, bool allowInterrupts)
     }
 }
 
-std::string readLine(int fd, bool eofOk)
+std::string readLine(int fd, bool eofOk, char terminator)
 {
     std::string s;
     while (1) {
@@ -123,7 +123,7 @@ std::string readLine(int fd, bool eofOk)
             else
                 throw EndOfFile("unexpected EOF reading a line");
         } else {
-            if (ch == '\n')
+            if (ch == terminator)
                 return s;
             s += ch;
         }