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Size: 750
Comment: replacing subshell with grouping according to pgas's suggestion
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How to write several times to a fifo without having to reopen it?
The basic use of named pipes is:
cat < myfifo & echo 'a' > myfifo
this works but, cat dies after it. What if we want to write several times to the pipe without having to reopen it?
If the commands are consecutive, they can be grouped and redirect its output:
cat < myfifo &
{ echo 'a'; echo 'b'; echo 'c'; } > myfifoBut if they can't be grouped for some reason, a better way is to assign a file descriptor to the pipe and write there:
cat < myfifo & # assigning fd 3 to the pipe exec 3>myfifo # writing to fd 3 instead of the pipe echo 'a' >&3 echo 'b' >&3 echo 'c' >&3 # closing the fd exec 3>&-