Search results
Results from the WOW.Com Content Network
In Unix and Unix-like operating systems, printf is a shell builtin (and utility program [2]) that formats and outputs text like the same-named C function. Originally named for outputting to a printer, it actually outputs to standard output. [3] The command accepts a format string, which specifies how to format values, and a list of values.
The Unix system had been written almost exclusively in C, so the C shell's first objective was a command language that was more stylistically consistent with the rest of the system. The keywords, the use of parentheses, and the C shell's built-in expression grammar and support for arrays were all strongly influenced by C.
This is the primary way to output data from a program by directly using a system call. The destination is identified by a numeric code. The data to be written, for instance a piece of text, is defined by a pointer and a size, given in number of bytes. write thus takes three arguments: The file code (file descriptor or fd).
The C programming language provides many standard library functions for file input and output.These functions make up the bulk of the C standard library header <stdio.h>. [1] The functionality descends from a "portable I/O package" written by Mike Lesk at Bell Labs in the early 1970s, [2] and officially became part of the Unix operating system in Version 7.
For most file systems, a program initializes access to a file in a file system using the open system call. This allocates resources associated to the file (the file descriptor), and returns a handle that the process will use to refer to that file. In some cases the open is performed by the first access.
Unix-like operating systems such as Linux have implemented 9P2000, Plan 9's protocol for accessing remote files, and have adopted features of rfork, Plan 9's process creation mechanism. [64] Additionally, in Plan 9 from User Space , several of Plan 9's applications and tools, including the sam and acme editors, have been ported to Unix and ...
Ian Darwin's implementation adds -s 'special files', -k 'keep-going' or -r 'raw' (examples below), among many others. [6] The command tells only what the file looks like, not what it is (in the case where file looks at the content). It is easy to fool the program by putting a magic number into a file the content of which does not match it.
printk is a C function from the Linux kernel interface that prints messages to the kernel log. [1] It accepts a string parameter called the format string, which specifies a method for rendering an arbitrary number of varied data type parameter(s) into a string. [1] The string is then printed to the kernel log. [1]