bash-echoing.md

Echo in bash

"$v" prevents pathname expansion or globbing and field splitting

parameter expansion need to use single quoting '$v' or escaping $v

single quotes prevent shell expansion

or for some expansion, use "$var $anothervar"

alos "${v}"

heredocs

https://en.wikipedia.org/wiki/Here_document

cat << EOF

asdasd EOF

EOF can be any indicator

<< vs <<- with -, in POSIZ shell, leading tabs are ignored, which has the effect of removing whitepsace in the output

output to file

$ cat << EOF > ~/testFile001

3 spaces precede this text. A single tab character is at the beginning of this line. Nothing precedes this text EOF

here string

$ LANG=C tr a-z A-Z <<< one ONE

https://linuxize.com/post/bash-heredoc/