Datasheet

“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 722 — #748

28.16 Specifying the Required Library:

ldd

With the command ldd, ﬁnd out which libraries the dynamic executable

speciﬁed as argument would be subsequently loaded:

$ ldd /bin/ls

linux-gate.so.1 => (0xffffe000)

librt.so.1 => /lib/tls/librt.so.1 (0x4002b000)

libacl.so.1 => /lib/libacl.so.1 (0x40033000)

libselinux.so.1 => /lib/libselinux.so.1 (0x40039000)

libc.so.6 => /lib/tls/libc.so.6 (0x40048000)

libpthread.so.0 => /lib/tls/libpthread.so.0 (0x4015d000)

/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)

libattr.so.1 => /lib/libattr.so.1 (0x4016d000)

Static binaries do not need any dynamic libraries:

$ ldd /bin/rpm

not a dynamic executable

$ file /bin/rpm

/bin/rpm: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), \

statically linked, stripped

28.17 Interprocess Communication:

ipcs

The command ipcs produces a list of the IPC resources currently in use:

$ ipcs

------ Shared Memory Segments --------

key shmid owner perms bytes nattch status

0x000027d9 5734403 toms 660 64528 2

0x00000000 5767172 toms 666 37044 2

0x00000000 5799941 toms 666 37044 2

------ Semaphore Arrays --------

key semid owner perms nsems

0x000027d9 0 toms 660 1

------ Message Queues --------

key msqid owner perms used-bytes messages

722

28.16. Specifying the Required Library: ldd