Bash: envsubst

welcome.txt

This is $FOO and this $BAR

usage

export FOO=foo export BAR=bar
# 全量替换
envsubst < welcome.txt
This is foo and this bar

# 部分替换
envsubst '$FOO' < welcome.txt
This is foo and this $BAR

# 多个变量
envsubst '$FOO,$BAR' < welcome.txt
This is foo and this bar

参考

• https://man7.org/linux/man-pages/man1/envsubst.1.html
• https://www.baeldung.com/linux/envsubst-command