How to print a string with a variable by using the echo command in the shell script All In One

Node.js & nvm

question

I defined a shell variable in the terminal and then used the echo command to output a string with that variable and it worked fine in the terminal.

But when I use the same command in a shell script, the variable disappears without any output or error.

So, what's going on.

terminal

$ NVM_USER=xgqfrms

$ echo $NVM_USER
xgqfrms

$ echo "string with a variable $NVM_USER"
string with a variable xgqfrms
$ echo string with a variable $NVM_USER
string with a variable xgqfrms
$ echo "string with a variable ${NVM_USER}"
string with a variable xgqfrms

shell script

#!/usr/bin/env bash

echo $NVM_USER
echo "string with a variable $NVM_USER"
echo string with a variable $NVM_USER
echo "string with a variable ${NVM_USER}"

I've searched and tried some solutions but still stuck.

update

It works using a variable defined in shell scripts.

#!/usr/bin/env bash

user=xgqfrms
echo "string with a variable ${user}"

# temp=$(echo $NVM_USER)
echo "string with a variable ${temp}"

solutions

1. when using the same terminal

# terminal
$ export NVM_USER=xgqfrms

$ ./test.sh

As answered by Gilles Quénot

2. when using different terminals

bash demo

# terminal 1

# 1. add your export variable to the shell config file
$ sudo vim .bashrc
export NVM_USER=xgqfrms

# fresh the config
$ source ~/.bashrc

# terminal 2
$ ./test.sh

zsh demo

# terminal 1

# 1. add your export variable to the shell config file
$ sudo vim .zshrc
export NVM_USER=xgqfrms

# fresh the config
$ source ~/.zshrc

demos

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标签：shell,string,script,echo,USER,xgqfrms,variable,NVM
From： https://www.cnblogs.com/xgqfrms/p/17719773.html