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.

Column

A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member. The term column applies especially to a large round support (the shaft of the column) with a capital and a base or pedestal and made of stone, or appearing to be so. A small wooden or metal support is typically called a post, and supports with a rectangular or other non-round section are usually called piers. For the purpose of wind or earthquake engineering, columns may be designed to resist lateral forces. Other compression members are often termed "columns" because of the similar stress conditions. Columns are frequently used to support beams or arches on which the upper parts of walls or ceilings rest. In architecture, "column" refers to such a structural element that also has certain proportional and decorative features. A column might also be a decorative element not needed for structural purposes; many columns are "engaged", that is to say form part of a wall.

Columns (band)

Columns is an American death metal/grindcore band from Charlotte, North Carolina, United States. The band formed in 2004. Vocalist Adam Cody is also the vocalist for Glass Casket and Victory Records' Wretched. Jason Skipper and Jake Wade are also currently members in the punk band One Another. Guitarist Michael Lehmann was an original member of the goregrind band Hemdale. Jake Troth, also of Glass Casket, was an original member of Columns who left the band in 2007.

Columns signed with Relapse Records in June, 2013.

Members

Current line-up

Former members

Fill ins

Discography

Albums

EPs and demos

References

External links