error while loading shared library. cannot open shared object file

This occurs when it can't load a shared library, use "ldd(1)" to determine which libraries this program is trying to link against and which ones are missing or can't be linked against. eg

ldd /bin/cat

"No such file or directory"

If you see this message when trying to run a program, even though you can plainly see it right in front of you, there are a couple of possibilities:

• If it is some kind of script, it might point to an interpreter that doesn't exist on your system. For example, it used to be common to see perl scripts whose first line was

  1. /usr/local/bin/perl

But if you had perl installed as /bin/perl or /usr/bin/perl you would get this message.

• Your dynamic binary executable is linked against a specific dynamic library on your system that has the same name (but different binary interfaces??) as the machine that the file was compiled on. This is particularly annoying as you can also get this message when trying to use ldd(1) to find out which dynamic library is causing the problem! If ldd(1) doesn't work, you are probably missing /lib/ld.so or /lib/ld-linux.so
• More commonly this program is linked against a library that doesn't exist on your machine. If all your programs are saying this, try echo /lib/*, you'll probably find it empty :)

Xlib: connection to ":0.0" refused by server

Xlib: connection to ":0.0" refused by server Xlib: Client is not authorized to connect to Server some_app: unable to open display ":0.0"

The user running the command is different to the user that started the X-server, or is otherwise not allowed by the X server to create new (graphical) windows.

Also see the XAuthNotes? page on giving other users permission to open graphical windows on your X server.

-bash: /bin/bash: Permission denied: /path/to/program

bash: /path/to/script: /bin/bash: bad interpreter: Permission denied

Note that other shells (such as zsh(1)) don't give the "bad interpreter" part of the message for some of the following circumstances - only bash(1) seems to.

Possible causes for this message (in decreasing order of probability):

• /bin/bash exists and runs fine; the probable cause is the program is a script and the "u+x" bit is not set on the script. ("chmod a+x program" would also set it.) Bash will report this even if the script is not a bash script - that is because bash has to first load and run the script, which is can't do.
• This error occurred on my system on the /var directory because /dev/hda5 was mounted on /var with the option "noexec". This is also the case for CDROMs and floppy drives - by default in many distributions you can't run executables from removable media. (This is caused by the "user" mount option.)
• It is possible (but very unlikely) that /bin/bash (or whatever shell the script uses) isn't executable, and since it is a bash script the kernel is trying to start bash.

chmod a+rx /bin/bash /usr/bin/perl /usr/local/bin/perl /path/to/your/script/here

this will mark these all as executable and readable by everyone.

• It is possible that the interpreter being used is not runable, for example it has unresolved link dependencies as described earlier in the page.
• I got errors similar to this when my locale files were generated incorrectly (I was using Debian at the time). Originally I thought I had suffered filesystem corruption, as the output of ls(1) was rubbish, and no text scripts would run, although binaries were fine. Specifically, the LC_CTYPE environment variable was defaulting to en_US.UTF-8 but locale-gen(8) had somehow generated the wrong encoding. Anyway, doing LC_ALL=C ; export LC_ALL

changed it back to using ascii(7) characters, and my scripts ran again.

• Mandrake 9.1 using the secure kernel: this error occurs when the directory containing the script is world writable. e.g.: the script /!MyDir?/myscript.sh will give this error if the directory /!MyDir? is world-writable. chmod 700 /!MyDir? and try again :)

ping: unknown protocol icmp

cobalt root # ping ping: unknown protocol icmp.

I googled for this, and only found suggestions to make sure /proc was mounted (which it was) and that my interfaces were correctly configured (which they were, and I dont see why this would matter). I asked GreigMcGill, and he suggested /etc/protocols issues: my /etc/protocols was fine, BUT my system had taken upon itself to declare my LDAP server as authoritative for protocols in /etc/nsswitch.conf

protocols: ldap [NOTFOUND=return? files

Deleting the ldap portion (as I don't have protocols info in the LDAP tree) fixed

protocols: files.

ping: sendto: Operation not permitted

PING 192.168.66.10 (192.168.66.10): 56 data bytes ping: sendto: Operation not permitted ping: wrote 192.168.66.10 64 chars, ret=-1

The interface you are pinging out of (192.168.66.10) is firewalled. Fix your firewall :)

Your shell hangs

Your shell hangs, and it even ignores ctrl-c. You have to close the xterm (or gnome-terminal or konsole) to remove the process.

Possible answer: you have inadvertently typed the special "stop" flow control character used by terminals. By default, this is ^S (control-s). By default, control-q sends a start character again. This is particularly common if you were pressing ctrl-d or ctrl-a or a nearby key on a QWERTY keyboard.

You can use the stty(1) program to change this behaviour

$ stty -ixon

will tell your terminal not to use XON/XOFF flow control.

$ stty stop ""

will mean that no character sends a stop character.

$ stty stop " "

causes your terminal to stop every time you press space. This is probably not a very clever thing to do (unless you are playing a trick on someone...)

Re-defining the stop key has the added advantage that you can then use ctrl-s to search your command line in bash(1)/zsh(1) as well as ctrl-r for reverse search.

Kernel/libc Error Messages

See ErrorMessages

Error Messages for specific Applications

See ApplicationErrorMessages

Humorous Error Messages

FunnyApplicationErrorMessages