Unix Shell Scripting

1 ✘ null ✘ error ✔

a is not defined ✘ a is null ✘ a: command not found ✘ Hello ✔

World ✘ Hello World ✘ HelloWorld ✘ Error ✔

HelloWorld ✘ Hello World ✘ World ✘ Error ✔

PS0 ✘ PS1 ✘ PS2 ✘ PS ✔

9 ✘ 6 + 3 ✘ expr 6 + 3 ✘ error ✔

9 ✘ expr 6 + 3 ✘ 9 ✘ error ✔

Checks if file descriptor is open and associated with a terminal; if yes, then the condition becomes true. ✘ Checks if file is executable; if yes, then the condition becomes true. ✘ Checks if file exists; is true even if file is a directory but exists. ✘ Checks if file is an ordinary file as opposed to a directory or special file; if yes, then the condition becomes true. ✔

Checks if file is a named pipe; if yes, then the condition becomes true. ✘ Checks if file descriptor is open and associated with a terminal; if yes, then the condition becomes true. ✘ Checks if file is readable; if yes, then the condition becomes true. ✘ Checks if file is an ordinary file as opposed to a directory or special file; if yes, then the condition becomes true. ✔

Checks if file has its sticky bit set; if yes, then the condition becomes true. ✘ Checks if file is an ordinary file as opposed to a directory or special file; if yes, then the condition becomes true. ✘ Checks if file is readable; if yes, then the condition becomes true. ✘ Checks if file has size greater than 0; if yes, then condition becomes true. ✔