A non-quoted backslash ‘\’ is the Bash escape character. It preserves the literal value of the next character that follows, with the exception of newline. If a \newline pair appears, and the backslash itself is not quoted, the \newline is treated as a line continuation (that is, it is removed from the input stream and effectively ignored).

commannd1 arg1 arg2 \
arg3 arg4

OR

commannd1 -arg1 -arg2 \
-arg3 -arg4 \
-arg5 -arg6

Example

The following command is used to compile and install nginx web server. A backslash (\) is used as to continue command on the next line:

./configure --without-http_autoindex_module --without-http_ssi_module \
           --without-http_userid_module --without-http_auth_basic_module \
           --without-http_geo_module --without-http_fastcgi_module \
           --without-http_empty_gif_module  --with-openssl=/lib64