简单的格式化文本
fmt [option] [file-list]
fmt通过将所有非空白行的长度设置为几乎相同，来进行简单的文本格式化
参数
fmt从file-list中读取文件，并将其内容的格式化版本发送到标准输出。如果不制定文件名或者用连字符（-）来替代文件名，则fmt将从标准输入读取文本信息
选项
-s 截断长行，但不合并
-t 除每个段落的第1行外都缩进
-u 改变格式化，使字之间出现一个空格，句子之间出现两个空格
-w n 将输出的行宽改为n个字符。不带该选项时，fmt输出的行宽度为75个字符
示例
原文件
$ cat demo A long time ago, there was a huge apple tree. A little boy loved to come and play around it every day. He climbed to the tree top, ate the apples, took a nap under the shadow… He loved the tree and the tree loved to play with him.
fmt -s
$ fmt -s demo A long time ago, there was a huge apple tree. A little boy loved to come and play around it every day. He climbed to the tree top, ate the apples, took a nap under the shadow… He loved the tree and the tree loved to play with him.
截断长行
fmt -t
$ fmt -t demo A long time ago, there was a huge apple tree. A little boy lovedto come and play around it every day. He climbed to the tree top,ate the apples, took a nap under the shadow… He loved the tree andthe tree loved to play with him.
排除首行的缩进
fmt -u
$ fmt -u demo A long time ago, there was a huge apple tree. A little boy loved to come and play around it every day. He climbed to the tree top, ate the apples, took a nap under the shadow… He loved the tree and the tree loved to play with him.
格式化单词和句子的间隔，很明显A little boy那里的多个空格被截断到两个
fmt -w
$ fmt -w 40 demo A long time ago, there was a huge apple tree. A little boy loved to come and play around it every day. He climbed to the tree top, ate the apples, took a nap under the shadow… He loved the tree and the tree loved to play with him.
