Unix Tip: Clearing the screen

Every now and then I come across a system which, when I issue a request to clear the screen (i.e. the clear command), I get something like this instead:

oopsy# clear
ld.so.1: clear: fatal: libncurses.so.5: open failed: No such file or directory
Killed


Often, on encountering this problem, I simply growl, press enter a couple dozen times and continue working. When I'm in a particularly "fixit" mood, on the other hand, I figure I shouldn't be putting up with annoying configuration problems and decide to break my train of thought just long enough to tackle this distracting problem head-on.

So, what is going on when you get an error such as this?

First, we know it came about because I issued the "clear" command. Next, we see that the error was issued by ld.so.1 (the runtime linker). Third, we see that the linker wasn't able to open a particular shared object file; it couldn't find it. The shared object file, libncurses.so.5, as you might suspect is the curses library. Curses provides a set of functions that provide users with the ability to manipulate a terminal's display regardless of the terminal type; thus the problem arose when I attempted to clear the contents of a terminal window. The curses library contains routines to accomplish this task. When I ran into the error shown above, I figured that one of two things was true. Either the library wasn't installed on the system (maybe it had been removed) or the linker just couldn't find it. A quick scan of the system showed that the "missing" library was installed in /usr/local/lib.


oopsy# ls -l /usr/local/lib/libn*
-rwxr-xr-x 1 bin bin 247760 May 1 2001 /usr/local/lib/libncurses++.a
-rw-r--r-- 1 bin bin 453732 May 1 2001 /usr/local/lib/libncurses.a
lrwxrwxrwx 1 root root 15 May 20 2003 /usr/local/lib/libncurses.so -> libncurses.so.5
lrwxrwxrwx 1 root root 17 May 20 2003 /usr/local/lib/libncurses.so.5 -> libncurses.so.5.2
-rw-r--r-- 1 bin bin 338384 May 1 2001 /usr/local/lib/libncurses.so.5.2
-rw-r--r-- 1 bin bin 3459752 May 1 2001 /usr/local/lib/libncurses_g.a


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