Can bash variables have dashes?

Can bash variables have dashes?

# As of version 3 of Bash, periods are not allowed within variable names. Using a hyphen or other reserved characters in a variable name (or function name). Using the same name for a variable and a function. This can make a script difficult to understand.

What is the difference between echo and print in shell script?

echo always exits with a 0 status, and simply prints arguments followed by an end of line character on the standard output, while printf allows for definition of a formatting string and gives a non-zero exit status code upon failure.

How do I print echo in New Line?

4 Answers. That is, echo without any arguments will print a blank line. This works more reliably in many systems, though it’s not POSIX compliant. Notice that you must manually add a \n at the end, as printf doesn’t append a newline automatically as echo does.

How do I print echo without newline?

Let’s go over it step by step:

1. Press ‘Windows’ and ‘R’ key at the same time to open the ‘Run’ window.
2. Type ‘cmd’ in the Open box.
3. Type the following command in Command Prompt: echo | set /p=your text or variable (in this example it’s ‘1’)
4. Press ‘Enter’ to execute this command.
5. You should not see a new line in between.

Can variable name have dash?

A ‘word’ consisting solely of letters, numbers, and underscores, and beginning with a letter or underscore. ‘Name’s are used as shell variable and function names. Also referred to as an ‘identifier’. So you can’t use a hyphen in a name.

What is dash in bash?

More precisely, a double dash ( — ) is used in most Bash built-in commands and many other commands to signify the end of command options, after which only positional arguments are accepted. Most notably in the Bash set built-in, where it’s absolutely necessary.

What does the command echo $$ print in a Bash shell?

echo command in linux is used to display line of text/string that are passed as an argument . This is a built in command that is mostly used in shell scripts and batch files to output status text to the screen or a file.

How do I go to a new line in terminal?

Just wanted to add that in case you’re typing a long line of code and wanted to break it up for aesthetic reasons, hitting shift + enter forces the interpreter to take you to a new line with the prompt.

How do you print a new line in Unix?

Uses of \n in Bash

1. String in double quote: echo -e “This is First Line \nThis is Second Line”
2. String in single quote: echo -e ‘This is First Line \nThis is Second Line’
3. String with $ prefix: echo $’This is First Line \nThis is Second Line’
4. Using printf command: printf “This is First Line \nThis is Second Line”

How do I echo a tab in bash?

How to echo a tab in bash? Answer: In Bash script, if you want to print out unprintable characters such as tab, you need to use -e flag together with the echo command.

Are there only bash built-ins in echo statement?

There are only bash built-ins in the echo statement. So, we can use it in cycle. Note there will be only 3 ‘%’ in created sequence. Not the answer you’re looking for? Browse other questions tagged bash shell or ask your own question.

Which is the best way to not use echo?

The best solution is not to use echo, but to use printf instead. …meaning you don’t need to do any special preparation/modification elsewhere in your code based on the knowledge that a value will be echo d.

How does the behaviour of Bash Echo depend on the environment?

The behaviour of bash ‘s echo builtin may depend on bash version. It also depends on the environment ( POSIXLY_CORRECT, SHELLOPTS and BASHOPTS variables), the options ( posix, xpg_echo ), the build options and argv [0] ( sh vs bash ). Here tested with GNU bash 4.2.53 (1), default build, default options, empty environment, invoked as bash.

Is the ECHO command unportable in POSIX shell?

Incidentally, the POSIX shell command specification for echo acknowledges that it is unportable as implemented, and contains a note on that subject: It is not possible to use echo portably across all POSIX systems unless both -n (as the first argument) and escape sequences are omitted.