Variable is not null unix

Ask Question. Asked 7 years, 9 months ago. Active 1 year, 6 months ago. Viewed 66k times. Are you sure you should convert it to tcsh? That is not an answer to the question asked. The question was TCSH. Add a comment. Active Oldest Votes. Note: This will break if name is an environment variable. But bash has a feature to do this task. How you can check the variable is set or not in bash is shown in this tutorial. Syntax: [ [ -v variable ] ] Or [ [ -z variable ] ].

Fahmida Yesmin I am a trainer of web programming courses. Or more simple approach somewhat "hackish" setting val to "unitialized" or to some other value which can't appear when running your program.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. How to check if the variable value in AWK script is null or empty? Ask Question. Asked 9 years, 5 months ago. Active 3 years, 5 months ago. Viewed k times. I am using AWK script to process some logs. Search Forums. Show Threads. Show Posts. Shell Programming and Scripting. Registered User. Join Date: Nov Administrator Emeritus.

Join Date: Aug The first one is right if you put a space before the -z. For the second one switch to -n to test for non-null. Check null values column.