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
History of bottle recycling in the United States companies soon started using PET to package their drinks. Over the past 20 years or so, PET bottles (Polyethylene terephthalate) have become the most common material to package beverages, replacing glass and metal. Especially water and soda was starting to be packaged in PET bottles. This is because PET has certain material properties that make it more favorable than glass or metal cans. Most importantly, PET is lightweight and difficult to break. Further, PET is clear and has "good barrier properties towards moisture and oxygen". Because of these qualities, PET has replaced glass bottles and metal cans in many instances,