How to find whether or not a variable is empty in Bash

by

In Bash at least the following command tests if $var is empty:

if [[ -z "$var" ]]; then
   # $var is empty, do what you want
fi

The command man test is your friend.

More Related Contents:

  1. While loop stops reading after the first line in Bash
  2. How can I compare numbers in Bash?
  3. Pipe output and capture exit status in Bash
  4. Redirect stderr and stdout in Bash [duplicate]
  5. Which characters need to be escaped when using Bash?
  6. How to put a line comment for a multi-line command [duplicate]
  7. Why does “local” sweep the return code of a command?
  8. bash : Illegal number
  9. Batch renaming files with Bash
  10. Shell redirection i/o order
  11. How to generate random number in Bash?
  12. In bash, how do I bind a function key to a command?
  13. “Invalid Arithmetic Operator” when doing floating-point math in bash
  14. Using sed to mass rename files
  15. Colorized grep — viewing the entire file with highlighted matches
  16. How to pass in password to pg_dump?
  17. Select random lines from a file
  18. Variables getting reset after the while read loop that reads from a pipeline
  19. How to kill all subprocesses of shell?
  20. Should I use a Shebang with Bash scripts?
  21. Get current directory or folder name (without the full path)
  22. Execute a shell function with timeout
  23. Convert Unix timestamp to a date string
  24. Using Bash to display a progress indicator (spinner) [duplicate]
  25. Extract version number from a string
  26. How do I get both STDOUT and STDERR to go to the terminal and a log file?
  27. Use GNU find to show only the leaf directories
  28. Get the name of the caller script in bash script
  29. docker entrypoint running bash script gets “permission denied”
  30. What does `kill -0 $pid` in a shell script do?

Leave a Comment