I have a very long bash command inside a command substitution like following:
$( comaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaand ) I want to know if there is a way to break this command into shorter lines for the sake of readability like following:
$( com aaaaaaaaaaaaaa aaaaaaaaaaaaaa nd ) You can mask the newline with \.
$( com\ aaaaaaaaaaaaaa\ aaaaaaaaaaaaaa\ nd ) The \ tells the shell to ignore the newline.
\ part is correct, but you can not indent the subsequent lines. (At least not in the middle of words as in the example.) commaaaaaaaaaaaaaand is actually command with a lot of options and | maybe pipes etc. Otherwise it doesn't work with indentation.Try echo $(ec\<NEWLINEHERE>ho a), works while echo $(ec\<NEWLINE HERE><INDENTATION HERE>ho a) produce ec: command not found. While echo $(echo Hello,\<NEWLINE HERE> World)[note the space after newline] and echo $(echo Hello,<NEWLINE HERE><INDENTATION HERE> World) do exactly the same things. echo "$(echo "Hello,\<NEWLINE HERE> World")" ) so the outer echo receives several parameters and separate them with only 1 default separator. If there are pipe | symbols in a long Bash command line, there may be no need for the backslash \ to mask the newline because the pipe | symbols can be used for formatting your code as well.
# example ls | cat -n | tail | head 