bash redirecting EOF into variable

Question

this is my file perl5lib.sh:

export PERL5LIB=`cat |tr '\n' ':'`<<EOF
/home/vul/repository/projects/implatform/daemon/trunk/lib/
/home/vul/repository/projects/platformlib/tool/trunk/cpan_lib
/home/projects/libtrololo

I want to start file as

. perl5lib.sh

to populate PERL5LIB variable, but it hangs. What is wrong? my goal is to left folder names at the end of file, so I can add new simply:

echo dirname >> myscript

I have tried and export PERL5LIB=$(echo blabla) and cat<<EOF both work separately, but not together.

=================== THE SOLUTION ============================

function do the trick!

function fun
{
     export PERL5LIB=`cat|tr '\n' ':'`
}
fun<<EOF
/dir1/lib
/dir2/lib
/dir3/lib
EOF

This should not work. It should complain about a missing here-document terminator. And there's a useless `cat` as well. — Jens, Oct 12 '12 at 13:13
your "function do the trick!" section spawns two extra child processes — bobah, Oct 12 '12 at 15:30
Please remove the "does the trick" section and accept one of the answers (or make it an answer and accept it). — einpoklum, Apr 19 '13 at 06:27

score 4 · Accepted Answer · answered Oct 12 '12 at 08:34

cat is useless here. Provide EOF inside the subshell:

#! /bin/bash
export PERL5LIB=$(tr '\n' ':'<<EOF
/home/vul/repository/projects/implatform/daemon/trunk/lib/
/home/vul/repository/projects/platformlib/tool/trunk/cpan_lib
/home/projects/libtrololo
EOF
)

score 4 · Answer 2 · answered Oct 12 '12 at 08:41

What you call "EOF" can be googled as Here Document. Here Document can only be used to feed the standard input of a command. The below example does what you want without spawning child processes

#!/bin/bash

multilineconcat=
while read line; do
  #echo $line
  multilineconcat+=$line
  multilineconcat+=":"
done << EOF
path1
path2
EOF

echo $multilineconcat

Brian Agnew · Answer 3 · 2012-10-12T13:13:25.293

2

Isn't it waiting for the EOF in your heredoc ?

I'd expect you to say

$ mycommand <<EOF
input1
input2
...
EOF

Note that EOF isn't a magic keyword. It's just a marker, and could be anything (ABC etc.). It indicates the end-of-file, but people simply write EOF as convention.

edited Oct 12 '12 at 13:13

answered Oct 12 '12 at 08:26

Brian Agnew

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No, EOF here is just a literal string. – chepner Oct 12 '12 at 12:12

bash redirecting EOF into variable

function do the trick!

3 Answers3