output redirection using exec command
Hi team,
below is the program i have written to redirect the output to file using my own file descriptor. Iam able to successfully redirect the output to a file .
But the problem iamm facing is that , after closing my file descriptor still my programs writes the output to the file
How to solve this problem , any help is really appreciated
#script5
#!/bin/bash
#script to create our own file descriptor
exec 4>fileout
#redirect standard output to file descriptor 4
exec 1>&4
echo "This is a test program"
exec 4&-
echo " Back to normal"
# i want the output back to normal to be displayed on the screen , but it is getting stored in the file
Any help is really appreciated.
below is the program i have written to redirect the output to file using my own file descriptor. Iam able to successfully redirect the output to a file .
But the problem iamm facing is that , after closing my file descriptor still my programs writes the output to the file
How to solve this problem , any help is really appreciated
#script5
#!/bin/bash
#script to create our own file descriptor
exec 4>fileout
#redirect standard output to file descriptor 4
exec 1>&4
echo "This is a test program"
exec 4&-
echo " Back to normal"
# i want the output back to normal to be displayed on the screen , but it is getting stored in the file
Any help is really appreciated.
Do more with
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
You'll end up with far more robust code by simply doing an echo to a specific file number, rather than trying to merge/unmerge various file numbers...
Using exec is far more complex than docs suggest. Try this instead...
Using exec is far more complex than docs suggest. Try this instead...
echo "This is a test program" >&4
exec 4>fileout
exec 1>&4
echo "This is a test program"
This assign the FD=4 to fileout
then it dup()'s FD=4 to FD=1 (closing original FD=1)
exec 4&-
Will dup() FD=4 to another FD>10. (oh btw. there needs to be a > or < with &-...)
There is nothing that will bring the original fd=1 back.
echo >fileout "This should be in Fileout"
echo "and this not"
should work a lot better...
Otherwise you need a subshell. / different shell
exec 1>&4
echo "This is a test program"
This assign the FD=4 to fileout
then it dup()'s FD=4 to FD=1 (closing original FD=1)
exec 4&-
Will dup() FD=4 to another FD>10. (oh btw. there needs to be a > or < with &-...)
There is nothing that will bring the original fd=1 back.
echo >fileout "This should be in Fileout"
echo "and this not"
should work a lot better...
Otherwise you need a subshell. / different shell
Thanks noci and david , below is the code iam implemented
now it is working
script5
#!/bin/bash
#script to create our own file descriptor
exec 4>fileout
exec 5>&1
#redirect standard output to file descriptor 4
exec 1>&4
echo "This is a test program"
exec 4>&-
exec 1>&5
echo " Back to normal"
exec 5>&-
now it is working
script5
#!/bin/bash
#script to create our own file descriptor
exec 4>fileout
exec 5>&1
#redirect standard output to file descriptor 4
exec 1>&4
echo "This is a test program"
exec 4>&-
exec 1>&5
echo " Back to normal"
exec 5>&-
Premium Content
You need an Expert Office subscription to comment.Start Free Trial