I'm very simply wondering if, in a bash script, a new line is functionally 100% equivalent to &&?
e.g.:
#!/bin/bash 7z x "${file}" mv "${file}" "${new_file}" vs
#!/bin/bash 7z x "${file}" && mv "${file}" "${new_file}" GNU bash, version 5.1.16(1)-release (x86_64-pc-linux-gnu)
No: && only runs the command following it if the command preceding it succeeds. Thus
7z x "${file}" && mv "${file}" "${new_file}" only renames the file if 7z completes successfully, whereas
7z x "${file}" mv "${file}" "${new_file}" will run mv in all cases (and fail if ${file} doesn’t exist).
See What are the shell's control and redirection operators? for details (in particular, it describes how new lines are also not quite the same as ;).
$file is a parameter that should be 7z x -- "$file" and mv -- "$file" "$new_file" (NB some people seem to think that ${var} is equivalent to "$var") set -e at the beginning of the second example? Would it then behave the same as the first snippet? $A as "$A" prevents shell expanding A into multiple words. Writing $A_B as ${A}_B prevents shell trying to expand an unknown variable A_B instead of expanding A and appending _B. Many of the extended expansions (array, substring, trimming) require the {..} to control the internal syntax. 7z … && mv … will only run mv if 7z succeeds, but will continue running after mv if 7z fails; whereas set -e; 7z …; mv … will exit if any command fails, including mv, and anything following mv won’t run if 7z or mv fails.