Can anyone explain this behavior? Running:
#!/bin/sh
echo "hello world" | read var1 var2
echo $var1
echo $var2
results in nothing being ouput, while:
#!/bin/sh
echo "hello world" > test.file
read var1 var2 < test.file
echo $var1
echo $var2
produces the expected output:
hello
world
Shouldn't the pipe do in one step what the redirection to test.file did in the second example? I tried the same code with both the dash and bash shells and got the same behavior from both of them.
A recent addition to bash is the lastpipe option, which allows the last command in a pipeline to run in the current shell, not a subshell, when job control is deactivated.
#!/bin/bash
set +m # Deactiveate job control
shopt -s lastpipe
echo "hello world" | read var1 var2
echo $var1
echo $var2
will indeed output
hello
world