Leaving aside domain specific languages (for instance SQL or TeX), I've been able to do my jobs for the past 20 years using Perl, C, shell (+ standard toolset, including awk). I only program in other languages than Perl, C or shell if it's a matter of modifying existing code.

Perl is my first choice when writing something new, but I use C if either the programs running time is important and Perl is too slow (that's seldomly the case), or when I need to do something that's either quite bare-bones and/or system specific. And I use shell (or C) if I need to code something for a platform where Perl isn't available. Part of my job involves writing code for small machines, that neither have the disk space to install Perl, nor have the memory to run it.

That doesn't mean other languages couldn't do the job. Java, Python, .NET, Ada, whatever, they all could replace Perl easily. But the combination Perl+C+shell does a complete coverage of the solution space I've encountered. But where I can imagine Perl being replaced - I could not fanthom to be "complete" without C, or without the shell.