&& do_something...
}
main
七、每一行只做一件事
用反斜杠来作分隔符。例如：
temporary_files() {
local dir=$1
ls $dir | grep pid | grep -v daemon
}
可以写得简洁得多：
temporary_files() {
local dir=$1
ls $dir
| grep pid
| grep -v daemon
}
符号在缩进行的开始
符号在行末的坏例子：（译注：原文在此例中用了temporary_files()代码段，疑似是贴错了。结合上下文，应为print_dir_if_not_empty()）
print_dir_if_not_empty() {
local dir=$1
is_empty $dir &&
echo "dir is empty" ||
echo "dir=$dir"
}
好的例子：我们可以清晰看到行和连接符号之间的联系。
print_dir_if_not_empty() {
local dir=$1
is_empty $dir
&& echo "dir is empty"
|| echo "dir=$dir"
}
八、打印用法
不要这样做：
echo "this prog does:..."
echo "flags:"
echo "-h print help"
它应该是个函数：
usage() {
echo "this prog does:..."
echo "flags:"
echo "-h print help"
}
echo在每一行重复。因此我们得到了这个文档：
usage() {
cat <<- EOF
usage: $PROGNAME options
Program deletes files from filesystems to release space.
It gets config file that define fileystem paths to work on, and whitelist rules to
keep certain files.
OPTIONS:
-c --config configuration file containing the rules. use --help-config to see the syntax.
-n --pretend do not really delete, just how what you are going to do.
-t --test run unit test to check the program
-v --verbose Verbose. You can specify more then one -v to have more verbose
