Oh ok so basically for the most part backticks are not required. But for some reason, I remember when I was writing another program, I had to put the backticks in or it just wasn't working. Is there a scenario where backticks are required?
You have used backticks probably like below (in echo (print) statement ) but not csh because of its hang may cause of a bug when use bactick with tcsh..
you can maybe update tcsh with related patch or upgrade with a newer version then try again with backticks
regards
ygemici
Backticks have one and precisely one function: They turn a program's output into a parameter or string.
If you're throwing around backticks everywhere until a program "works" you are misusing them. Only use them where you want to capture a program's output into a parameter or string.
parent shell is waiting for execute of return value (file , command , variable , or any result..) that in backticks expression.firstly a new shell is executed and switching in.in new child shell , but commands are executed that is not efficiently work so does not produce any output.however parent shell is waiting still the result of it's and therefore probably commands can not see on stdoutput in this shell (probably non-access to terminal device via stdoutput because of ` ` backticks are still open so uncompleted and subshell has not it's own stdoutput fd!! )
firstly lets see wait issue effect these with backticks
for this i added the end of file an `echo`
and then execute a new shell
i am in a new shell now
# echo "wheres is results my commands "
nothing displayed..but commands are running!
parent shell is try to execute result in backticks so it will try to execute "UNIX.com" when exit the subshell
in subshell
nothing displayed again!.
try vim
so vim cant access to terminal , let see so why.
in parent shell
check the shells
Besides, as seen in above there is not a map with terminal and stdoutput in new shell with backticks..
last of all , in your script bash and ksh is seem success , csh is hanging (but in fact none of the successful)
as a result backticks are un-needed when they already will execute the commands by current shell.
Even better than using backticks, when you want to capture output of command, is $(). Like:
Which is the same as
except you can use the $() construct nested, whereas backticks not.
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