$6.$is a command in Bash shell language, when you try to set a variable, it is visibleor exported to any subprocess started from that instance of bash.a$)$ Importb$)$ Exportc$)$ Opend$)$ Close$7.$ Among the following command which is used with vi editors to delete a single character?a$)$ Ab$)$ Xc$)$ Yd$)$ z$8.$ Which of the following commands is used to display and create files?a$)$ catb$)$ cutc$)$ created$)$ mkfile$9.$ What is the core of the Linux operating system?a$)$ Terminal b$)$ Kernalc$)$ Commandd$)$ Application$10.$ OSS stands fora$)$ Open System Softwareb$)$ Open Source Softwarec$)$ Open Source Systemd$)$ Open System Server$11.$ Which of the following command is used to change the working directory?a$)$ Changedb$)$ Cdc$)$ Chdr d$)$dr$12\mathrm{.}13\mathrm{.}14\mathrm{.}15.$command is used to display the required number of lines at the end of the files.a$)$ Head b$)$ Top c$)$ Bottomd$)$ Tailcommand is used to display a message on the terminal.a$)$ Msgb$)$ Messagec$)$ Echod$)$ ecocommand is used to know the current working directorya$)$ Cwd b$)$ Wrk dirc$)$ Pwdird$)$ pwdcommand is used to create a directory.a$)$ Crtdir b$)$ Mkdir c$)$ Ctdir d$)$ Make dir$16.$ Which command is called as the end$-$of$-$file command?a$)$ Ctri$+$ V b$)$ Ctrl$+$ Bc$)$ Ctrl$+$ Dd$)$ Ctri$+$ C$17.$ Which of the following is called as the piping symbol?