Apr 3, 2012 · What does a dollar sign followed by an at-sign (@) mean in a shell script? For example: umbrella_corp_options $@

I'm trying to learn shell scripting, and I need to understand someone else's code. What is the $? variable hold? I can't Google search the answer because they block punctuation characters.

Dec 14, 2024 · Shell - "Shell" is a program, which facilitates the interaction between the user and the operating system (kernel). There are many shell implementations available, like sh, Bash, C shell, Z shell, etc.

$(command) is “command substitution”. As you seem to understand, it runs the command, captures its output, and inserts that into the command line that contains the $(…); e.g., $ ls -ld $(date +%B).txt -rwxr-xr-x 1 Noob Noob 867 Jul 2 11:09 July.txt ${parameter} is “parameter substitution”. A lot of information can be found in the shell’s man page, bash (1), under the “ …

I can't seem to be able to increase the variable value by 1. I have looked at tutorialspoint's Unix / Linux Shell Programming tutorial but it only shows how to add together two variables. I have tr...

Sep 14, 2012 · In Bash, there appear to be several variables which hold special, consistently-meaning values. For instance, ./myprogram &; echo $! will return the PID of the process which backgrounded myprog...

The shell is the program which actually processes commands and returns output. Most shells also manage foreground and background processes, command history and command line editing. These features (and many more) are standard in bash, the most common shell in modern linux systems. A terminal refers to a wrapper program which runs a shell.

It depends on the Test Construct around the operator. Your options are double parentheses, double brackets, single brackets, or test. If you use ((…)), you are testing arithmetic equality with == as in C: $ (( 1==1 )); echo $? 0 $ (( 1==2 )); echo $? 1 (Note: 0 means true in the Unix sense and a failed test results in a non-zero number.) Using -eq inside of double parentheses is …

When going through one shell script, I saw the term "$?". What is the significance of this term?

Sep 30, 2010 · You are not asking about shell conditions but test conditions. The whole expression in your example is evaluated by test ([) and not by the shell. The shell evaluates just the exit status of [.