I've seen hundreds of job descriptions online that list desired or required sysadmin skills and they usually include knowledge or competency in shell scripting and at least one programming language. There's no industry-wide standard for a favored language requirement for sysadmins but the trend is toward automation and agility.
Shell scripting is a must-have skill for sysadmins. Scripting common tasks and scheduling them via cron is essential for the proper care and feeding of Linux server systems. This level of automation can help with system security, common directory cleanup, general housekeeping, locking of unused accounts, and much more.
Programming languages have so many applications and possibilities that they're too numerous to list, although automation and security are at the top of that list. You also have maintenance tasks for existing applications written in compiled and parsed languages as well. Sysadmins are frequently called upon to fix minor security or coding issues in applications and a working knowledge of C-based languages helps with those tasks.
I'm interested to find out which languages you use for automation, programming, and taking care of those administrative tasks.