How to assign a heredoc value to a variable in Bash?

by

You can avoid a useless use of cat and handle mismatched quotes better with this:

$ read -r -d '' VAR <<'EOF'
abc'asdf"
$(dont-execute-this)
foo"bar"''
EOF

If you don’t quote the variable when you echo it, newlines are lost. Quoting it preserves them:

$ echo "$VAR"
abc'asdf"
$(dont-execute-this)
foo"bar"''

If you want to use indentation for readability in the source code, use a dash after the less-thans. The indentation must be done using only tabs (no spaces).

$ read -r -d '' VAR <<-'EOF'
    abc'asdf"
    $(dont-execute-this)
    foo"bar"''
    EOF
$ echo "$VAR"
abc'asdf"
$(dont-execute-this)
foo"bar"''

If, instead, you want to preserve the tabs in the contents of the resulting variable, you need to remove tab from IFS. The terminal marker for the here doc (EOF) must not be indented.

$ IFS='' read -r -d '' VAR <<'EOF'
    abc'asdf"
    $(dont-execute-this)
    foo"bar"''
EOF
$ echo "$VAR"
    abc'asdf"
    $(dont-execute-this)
    foo"bar"''

Tabs can be inserted at the command line by pressing Ctrl–V Tab. If you are using an editor, depending on which one, that may also work or you may have to turn off the feature that automatically converts tabs to spaces.

More Related Contents:

  1. here-document gives ‘unexpected end of file’ error
  2. How can I write a heredoc to a file in Bash script?
  3. How to avoid heredoc expanding variables? [duplicate]
  4. Using variables inside a bash heredoc
  5. How to suppress variable substitution in bash heredocs
  6. Passing a variable to a remote host in a bash script with ssh and EOF [duplicate]
  7. Indenting heredocs with spaces
  8. What’s the difference between “here string” and echo + pipe
  9. Bash: warning: here-document at line delimited by end-of-file (wanted `EOF’) [duplicate]
  10. Can I export a variable to the environment from a Bash script without sourcing it?
  11. Passing arguments to an interactive program non-interactively
  12. How to urlencode data for curl command?
  13. How to define hash tables in Bash?
  14. Assigning default values to shell variables with a single command in bash
  15. Why isn’t tilde (~) expanding inside double quotes? [duplicate]
  16. sed search and replace strings containing / [duplicate]
  17. How to echo shell commands as they are executed
  18. bash: shortest way to get n-th column of output
  19. Calling shell functions with xargs
  20. Openssh Private Key to RSA Private Key
  21. Parse out key=value pairs into variables
  22. How to split a string in shell and get the last field
  23. How do I make this file.sh executable via double click?
  24. What is
  25. How to write a bash script to set global environment variable?
  26. Hiding secret from command line parameter on Unix
  27. Bash Script Binary Search
  28. Escaping forward slashes in sed command [duplicate]
  29. Convert a string into an array with bash, honoring quotes for grouping [duplicate]
  30. How to include nohup inside a bash script?

Leave a Comment