Environment variables are a set of dynamic named values that can affect the way running processes will behave on a computer.
They are part of the environment in which a process runs. For example, a running process can query the value of the TEMP environment variable to discover a suitable location to store temporary files, or the HOME or USERPROFILE variable to find the directory structure owned by the user running the process.
They were introduced in their modern form in 1979 with Version 7 Unix, so are included in all Unix operating system flavors and variants from that point onward including Linux and OS X. From PC DOS 2.0 in 1982, all succeeding Microsoft operating systems including Microsoft Windows, and OS/2 also have included them as a feature, although with somewhat different syntax, usage and standard variable names.
In all Unix and Unix-like systems, each process has its own separate set of environment variables. By default, when a process is created, it inherits a duplicate environment of its parent process, except for explicit changes made by the parent when it creates the child. At the API level, these changes must be done between running fork
and exec
. Alternatively, from command shells such as bash, a user can change environment variables for a particular command invocation by indirectly invoking it via env
or using the ENVIRONMENT_VARIABLE=VALUE <command>
notation. All Unix operating system flavors, DOS, and Windows have environment variables; however, they do not all use the same variable names. A running program can access the values of environment variables for configuration purposes.
CLS may refer to:
In computing, CLS
(for clear screen) is a command used by the command line interpreters COMMAND.COM and CMD.EXE on DOS, OS/2 and Microsoft Windows operating systems to clear the screen or console window of commands and any output generated by them. It does not clear the user's history of commands, however. The command is also available in the DEC RT-11 operating system. In other environments, such as Linux and Unix, the same functionality is provided by the clear command.
While the ultimate origins of using the three-character string CLS as the command to clear the screen likely predate Microsoft's use, this command was present before its MS-DOS usage, in the embedded ROM BASIC dialects Microsoft wrote for early 8-bit microcomputers (such as TRS-80 Color BASIC), where it served the same purpose. The MS-DOS dialects of BASIC written by Microsoft, BASICA and GW-BASIC, also have the CLS command as a BASIC keyword - as do various non-Microsoft implementations of BASIC such as BBC BASIC found on the BBC Micro computers. The CLS command is also present in BASIC versions for Microsoft Windows, however this generally clears text printed on the form, rather than the whole screen or controls on the form.
Ritz or The Ritz may refer to:
Ritz is a lunar impact crater that is located on the far side of the Moon, just beyond the eastern limb. This portion of the lunar surface is sometimes brought into view of the Earth under favorable conditions of libration and sunlight. The crater lies to the northwest of the prominent crater Sklodowska.
This is a heavily worn and eroded crater formation that has not retained much of its original structure. The outer rim is an irregular circular ridge that surrounds the interior floor. There are a pair of small craterlets in the western part of the interior. The satellite crater Ritz B is nearly attached to the northeastern outer rim.
By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Ritz.
The Ritz was a New York City rock club in the 1980s and early 1990s.
The Ritz was founded in 1980 by Jerry Brandt in the historic Webster Hall ballroom and concert space on 11th Street between Third and Fourth Avenues in the East Village neighborhood of New York City. The address was 119 East 11th Street. The Ritz focused primarily on live performances, often of newer acts, but also featured dancing. The Ritz was one of the first clubs to incorporate video screens into the club experience with a 30' screen and a projector which cost $120,000. MTV made its debut at The Ritz. In April 1989, The Ritz moved to the site of the former Studio 54 on 254 West 54th Street, where it was called "The New Ritz" and continued to host concerts for several years. From 1990 onward it reverted to the name "The Ritz." The original 11th Street space is now again known as Webster Hall.
The club received national attention after an antagonistic performance by Public Image Limited on May 15, 1981. They were a late substitution for Bow Wow Wow, who were originally scheduled to perform. The band was more interested in creating performance art than giving a traditional concert. To this end, they appeared onstage deliberately obscured by a projection screen and played their records through the club's public address system while playing entirely different music onstage. Taunted by lead singer John Lydon (formerly of the Sex Pistols), the Ritz's unhappy patrons rioted, throwing bottles and garbage cans, and pulling on the video screen that covered the front of the stage.