linux command in C/C++

[zzho039]

doing second year course in uni, just had a test.
one of the question is asking soemthing like with the following shell command:

cat ./thing1 | ./thing2 ./thing3 `./thing4`

Please choose one:
a) thing1 thing2 thing3 are probably programs and thing4 is a data file
b) thing1 thing2 thing4 are probably programs and thing3 is a data file
c) thing2 thing4 are probably programs and thing1 thing3 are probably data files
d) thing2 thing3 thing4 are probably programs and thing1 is a data file
e) thing1 thing2 thing3 thing4 are probably all programs


i was told that the correct answer is c, but why?
and any1 could explain the ./ infront of thing1, plz? isn't that a data file? why?
thanks

[gpraghuram]

doing second year course in uni, just had a test.
one of the question is asking soemthing like with the following shell command:

cat ./thing1 | ./thing2 ./thing3 `./thing4`

Please choose one:
a) thing1 thing2 thing3 are probably programs and thing4 is a data file
b) thing1 thing2 thing4 are probably programs and thing3 is a data file
c) thing2 thing4 are probably programs and thing1 thing3 are probably data files
d) thing2 thing3 thing4 are probably programs and thing1 is a data file
e) thing1 thing2 thing3 thing4 are probably all programs


i was told that the correct answer is c, but why?
and any1 could explain the ./ infront of thing1, plz? isn't that a data file? why?
thanks

As told by u C is the right answer.
./ refers to the current directory.

Raghuram

[sicarie]

As told by u C is the right answer.
./ refers to the current directory.

Raghuram

Right, but not entirely complete. The '.' refers to the current directory, the dot-slash together ( ./ ) mean "run in this directory," and will execute the programs/commands that are associate with things[1-4].

[mac11]

doing second year course in uni, just had a test.
one of the question is asking soemthing like with the following shell command:

cat ./thing1 | ./thing2 ./thing3 `./thing4`

Please choose one:
a) thing1 thing2 thing3 are probably programs and thing4 is a data file
b) thing1 thing2 thing4 are probably programs and thing3 is a data file
c) thing2 thing4 are probably programs and thing1 thing3 are probably data files
d) thing2 thing3 thing4 are probably programs and thing1 is a data file
e) thing1 thing2 thing3 thing4 are probably all programs


i was told that the correct answer is c, but why?
and any1 could explain the ./ infront of thing1, plz? isn't that a data file? why?
thanks

My take on it:

1. thing1 is likely to be a data file because it is being cat'ed - you can cat a program but that would be useless, usually if something is cat'ed it's a data file

2. thing2 is likely a program because it is having input piped to it - it makes no sense to pipe input to a data file (thats pipe '|' , not re-direct '>')

3. thing3 is likely a data file because it comes directly after thing2 without any pipe or semicolon or whatever that commonly is used in command to hook programs together in the command (looks like thing3 is a parameter to thing2)

4. thing4 is likely a program because it is surrounded by ` this indicates that the output of thing4 is also used as arguments to thing2