KAI T-50 Golden Eagle

The KAI T-50 Golden Eagle (골든이글) is a family of South Korean supersonic advanced trainers and light combat aircraft, developed by Korea Aerospace Industries (KAI) with the American aerospace company Lockheed Martin. The T-50 is South Korea's first indigenous supersonic aircraft and one of the world's few supersonic trainers. Development began in the late 1990s, and its maiden flight occurred in 2002. The aircraft entered active service with the Republic of Korea Air Force (ROKAF) in 2005.

The T-50 has been further developed into aerobatic and combat variants, namely T-50B, TA-50, and FA-50. The F-50 is another advanced fighter variant being considered. The T-50B serves with the South Korean air force's aerobatics team. The TA-50 light attack variant has been ordered by Indonesia. The Philippines ordered 12 units of the FA-50 variant. The T-50 is also being marketed as a candidate for the United States Air Force's next-generation T-X trainer programme. Thailand ordered 4 units of the T-50 advanced trainer variant.

Korea Train Express

Korea Train eXpress (KTX) is South Korea's high-speed rail system, operated by Korail. Construction began on the high-speed line from Seoul to Busan in 1992. KTX services were launched on April 1, 2004.

KTX operates from Incheon International Airport with stops at Seoul Station and Yongsan Station towards Busan and Gwangju. A new terminal in Seoul's Gangnam District is under construction at Suseo Station which is scheduled to open in 2016 along with intermediate stations in New Dongtan City and Seoul Subway Line 1's Jije Station in Pyeongtaek. A new line from Wonju to Gangneung is under construction to serve the 2018 Winter Olympics in Pyeongchang.

Top speed for trains in regular service is currently 305 km/h (190 mph), though the infrastructure is designed for 350 km/h (217 mph). The initial rolling stock was based on Alstom's TGV Réseau, and was partly built in Korea. The domestically developed HSR-350x, which achieved 352.4 km/h (219.0 mph) in tests, resulted in a second type of high-speed trains now operated by Korail, the KTX Sancheon. The next generation KTX train, HEMU-430X, achieved 421.4 km/h in 2013, making South Korea the world's fourth country after Japan, France and China to develop a high-speed train running on conventional rail above 420 km/h.

Environment variable

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.

Details

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

CLS may refer to:

Academic fields

Education

Societies and associations

Software and technology

CLS (command)

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.