builtin - How to use the read command in Bash? -

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when try use read command in bash this:

echo hello | read str echo $str

nothing echoed, while think str should contain string hello. can please me understand behavior?

the read in script command fine. however, execute in pipeline, means in subshell, therefore, variables reads not visible in parent shell. can either

  • move rest of script in subshell, too:

    echo hello | { read str   echo $str }

  • or use command substitution value of variable out of subshell

    str=$(echo hello) echo $str

    or more complicated example (grabbing 2nd element of ls)

    str=$(ls | { read a; read a; echo $a; }) echo $str

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