diff --git a/doc/user-guide b/doc/user-guide
index d37f30df..e4c960ea 100644
--- a/doc/user-guide
+++ b/doc/user-guide
@@ -189,6 +189,7 @@ Sortix comes with a number of home-made programs. Here is an overview:
* `mv` - move a file
* `pager` - display file page by page
* `pwd` - print current directory path
+* `realpath` - canonicalize filesystem paths
* `regress` - run system tests
* `rm` - remove file
* `rmdir` - remove empty directory
diff --git a/utils/.gitignore b/utils/.gitignore
index 89b3413a..3d64369e 100644
--- a/utils/.gitignore
+++ b/utils/.gitignore
@@ -30,6 +30,7 @@ mktemp
mv
pager
pwd
+realpath
rm
rmdir
sleep
diff --git a/utils/Makefile b/utils/Makefile
index 6668cb09..46df97a2 100644
--- a/utils/Makefile
+++ b/utils/Makefile
@@ -42,6 +42,7 @@ mktemp \
mv \
pager \
pwd \
+realpath \
rm \
rmdir \
sleep \
diff --git a/utils/realpath.cpp b/utils/realpath.cpp
new file mode 100644
index 00000000..aac2ee93
--- /dev/null
+++ b/utils/realpath.cpp
@@ -0,0 +1,114 @@
+/*******************************************************************************
+
+ Copyright(C) Jonas 'Sortie' Termansen 2015.
+
+ This program is free software: you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by the Free
+ Software Foundation, either version 3 of the License, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ more details.
+
+ You should have received a copy of the GNU General Public License along with
+ this program. If not, see .
+
+ realpath.cpp
+ Canonicalize filesystem paths.
+
+*******************************************************************************/
+
+#include
+#include
+#include
+#include
+#include
+#include
+
+static void compact_arguments(int* argc, char*** argv)
+{
+ for ( int i = 0; i < *argc; i++ )
+ {
+ while ( i < *argc && !(*argv)[i] )
+ {
+ for ( int n = i; n < *argc; n++ )
+ (*argv)[n] = (*argv)[n+1];
+ (*argc)--;
+ }
+ }
+}
+
+static void help(FILE* fp, const char* argv0)
+{
+ fprintf(fp, "Usage: %s [OPTION]... PATH...\n", argv0);
+ fprintf(fp, "Convert the paths to canonicalized absolute paths.\n");
+}
+
+static void version(FILE* fp, const char* argv0)
+{
+ fprintf(fp, "%s (Sortix) %s\n", argv0, VERSIONSTR);
+ fprintf(fp, "License GPLv3+: GNU GPL version 3 or later .\n");
+ fprintf(fp, "This is free software: you are free to change and redistribute it.\n");
+ fprintf(fp, "There is NO WARRANTY, to the extent permitted by law.\n");
+}
+
+int main(int argc, char* argv[])
+{
+ setlocale(LC_ALL, "");
+
+ int eol = '\n';
+ const char* argv0 = argv[0];
+ for ( int i = 1; i < argc; i++ )
+ {
+ const char* arg = argv[i];
+ if ( arg[0] != '-' || !arg[1] )
+ continue;
+ argv[i] = NULL;
+ if ( !strcmp(arg, "--") )
+ break;
+ if ( arg[1] != '-' )
+ {
+ while ( char c = *++arg ) switch ( c )
+ {
+ case 'z': eol = '\0';
+ default:
+ fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
+ help(stderr, argv0);
+ exit(1);
+ }
+ }
+ else if ( !strcmp(arg, "--help") )
+ help(stdout, argv0), exit(0);
+ else if ( !strcmp(arg, "--version") )
+ version(stdout, argv0), exit(0);
+ else if ( !strcmp(arg, "--zero") )
+ eol = '\0';
+ else
+ {
+ fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
+ help(stderr, argv0);
+ exit(1);
+ }
+ }
+
+ compact_arguments(&argc, &argv);
+
+ int result = 0;
+ for ( int i = 1; i < argc; i++ )
+ {
+ char* path = realpath(argv[i], NULL);
+ if ( !path )
+ {
+ error(0, errno, "%s", argv[i]);
+ result = 1;
+ continue;
+ }
+ fputs(path, stdout);
+ putchar(eol);
+ free(path);
+ }
+
+ return result;
+}