The traditional UNIX tail utility can print out lines from the end of a file. If the number of lines is not configured (i.e., tail FILE), tail would print out the last 10 lines of its input. Or we could trigger by calling tail -NUM FILE, for example tail -2 README to print the last 2 lines of the file README.
This program implements the tail command in C for the xv6 operating system.
$ tail README
To build xv6 on an x86 ELF machine (like Linux or FreeBSD), run "make". On non-x86 or → non-ELF machines (like OS X, even on x86), you will need to install a cross-compiler → gcc suite capable of producing x86 ELF binaries. See → http://pdos.csail.mit.edu/6.828/2014/tools.html. Then run "make → TOOLPREFIX=i386-jos-elf-". To run xv6, install the QEMU PC simulators. To run in → QEMU, run "make qemu". To create a typeset version of the code, run "make xv6.pdf". This requires the "mpage" → utility. See http://www.mesa.nl/pub/mpage/.
$ grep the README | tail
Version 6 (v6). xv6 loosely follows the structure and style of v6, xv6 borrows code from → the following sources: JOS (asm.h, elf.h, mmu.h, bootasm.S, ide.c, console.c, and → others) Plan 9 (entryother.S, mp.h, mp.c, lapic.c) In addition, we are grateful for → the bug reports and patches contributed by The code in the files that constitute xv6 is To run xv6, install the QEMU PC simulators. → To run in QEMU, run "make qemu". To create a typeset version of the code, run "make xv6.pdf". This requires the "mpage" → utility. See http://www.mesa.nl/pub/mpage/.
$ tail -2 README
To create a typeset version of the code, run "make xv6.pdf". This requires the "mpage" → utility. See http://www.mesa.nl/pub/mpage/.’’’