"UNIX User's Handbook, 2/e" will jump start your UNIX/Linux skills-while offering a useful refresher to those with at least some UNIX/Linux experience.

Practical techniques for system administration and performance analysis-Covers processes, startup and shutdown, filesystems, managing disk usage, backups, kernels, device files, software management, printing, and key sysadmin commands.
Detailed coverage of key UNIX utilities-Includes example-rich coverage of the vi editor, grep, awk, sed, and other key utilities.
Gives users hands-on help with the UNIX utilities that matter most-and provides practical pattern-matching techniques with a broad range of applications.