ldd.1: Add more detail on the output of ldd

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

diff --git a/man1/ldd.1 b/man1/ldd.1
index 60651f217194eecd428e01fa343b1c9554336b7d..6f653953d40003b1335b4968fd353fd4bba61084 100644 (file)
--- a/man1/ldd.1
+++ b/man1/ldd.1
@@ -20,18 +20,48 @@ ldd \- print shared object dependencies
 .B ldd
 prints the shared objects (shared libraries) required by each program or
 shared object specified on the command line.
-.SS Security
+An example of its use and output is the following:
+
+.nf
+
+$ \fBldd /bin/ls\fP
+        linux-vdso.so.1 (0x00007ffcc3563000)
+        libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f87e5459000)
+        libcap.so.2 => /lib64/libcap.so.2 (0x00007f87e5254000)
+        libc.so.6 => /lib64/libc.so.6 (0x00007f87e4e92000)
+        libpcre.so.1 => /lib64/libpcre.so.1 (0x00007f87e4c22000)
+        libdl.so.2 => /lib64/libdl.so.2 (0x00007f87e4a1e000)
+        /lib64/ld-linux-x86-64.so.2 (0x00005574bf12e000)
+        libattr.so.1 => /lib64/libattr.so.1 (0x00007f87e4817000)
+        libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f87e45fa000)
+.fi
+
 In the usual case,
 .B ldd
 invokes the standard dynamic linker (see
 .BR ld.so (8))
 with the
 .B LD_TRACE_LOADED_OBJECTS
-environment variable set to 1,
-which causes the linker to display the library dependencies.
-Be aware,
-however,
-that in some circumstances, some versions of
+environment variable set to 1.
+This causes the dynamic linker to inspect the program's dynamic dependencies,
+and find (according to the rules described in
+.BR ld.so (8))
+and load the objects that satisfy those dependencies.
+For each dependency,
+.BR ldd
+displays the location of the matching object
+and the (hexadecimal) address at which it is loaded.
+(The
+.I linux-vdso
+and
+.I ld-linux
+shared dependencies are special; see
+.BR vdso (7)
+and
+.BR ld.so (8).)
+.\"
+.SS Security
+Be aware that in some circumstances, some versions of
 .BR ldd
 may attempt to obtain the dependency information
 by directly executing the program.