True and false (commands) Bash: True and false (commands) In Unix-like operating systems, codice_1 and codice_2 are commands whose only function is to always return with a predetermined exit status. Programmers and scripts often use the exit status of a command to assess success (exit status zero) or failure (non-zero) of the command. The codice_1 and codice_2 commands represent the logical values of command success, because "true" returns 0, and "false" returns 1. The commands are usually employed in conditional statements and loops of shell scripts. For example, the following shell script repeats the "echo hello" loop until interrupted: while true do done The
Tin can manufacturers voluntarily eliminated lead seams in food cans. However, imported food cans continued to include lead soldered seams. In 1995 the US FDA issued a rule prohibiting lead soldered food cans, including both domestic and imported food cans. In modern times, the majority of food cans in the UK have been lined with a plastic coating containing bisphenol A (BPA). The coating prevents acids and other substances from corroding the tin or aluminium of the can, but leaching of BPA into the can's contents is currently (as of 2013) being investigated as a potential health hazard. Cans come in a