将换行符替换为

  tar -options -f dest source |回车。切-b1-$（tput cols）| sed -u'i\\o033 [2K | stdbuf -o0 tr'\n'\r'; echo 
 

说明：

• cut -b1-$（tput cols）：如果tar长于终端宽度，则截断tar的输出。




• sed -u'i\＼ 033o033 [2K'：在每行的开头插入一行空白。 sed的 -u 选项将其置于非缓冲模式。 stdbuf -oL sed'i\\033 [2K'也将同样有效。




• stdbuf -o0 tr'\n''\r'：使用 tr 交换换行符和回车符。 Stdbuf确保输出未缓冲；如果在行缓冲终端上没有 \n ，我们将看不到任何输出。




• echo ：输出最后一个换行符，以便终端提示符不会吃掉最后一行。

针对您的编辑建议的问题：

  x = 0; 
 echo -e’e [s]; 
 tar -options -f dest源|边读边；做
 echo -en \e [u 
 if [$ x gt 0];然后回显-en \e [ $ x B; fi; 
 echo -en \e [2K 
 echo -n $ line |削减-b1-$（tput cols）; 
让 x =（$ x + 1）％5; 
完成；回声; 
 

可以将所有内容随意粘贴到一行上。实际上，这为原始问题提供了另一种解决方案：

  echo -e’\e [s]; tar -options -f dest源|边读边；做echo -en \e [u\e2K; echo -n $ line |削减-b1-$（tput cols）;完成echo 
 

除了VT100代码外，它完全不依赖任何内容。

Is it possible to get the output of a command - for example tar - to write each line of output to one line only?

Example usage:

tar -options -f dest source | [insert trickery here]

and the output would show every file being processed without making the screen move: each output overwrites the last one. Can it be done?

---

Edit: we seem to have a working answer, but lets take it further: How about doing the same, but over 5 lines? You see a scrolling output that doesn't affect the rest of the terminal. I think I've got an answer, but I'd like to see what you guys think.

Replace the newlines with carriage returns.

 tar -options -f dest source | cut -b1-$(tput cols) | sed -u 'i\\o033[2K' | stdbuf -o0 tr '\n' '\r'; echo

Explanation:

• cut -b1-$(tput cols): Truncates the output of tar if it is longer than the terminal is wide. Depending on how little you want your terminal to move, it isn't strictly necessary.

• sed -u 'i\\o033[2K': Inserts a line blank at the beginning of each line. The -u option to sed puts it in unbuffered mode. stdbuf -oL sed 'i\\033[2K' would work equally as well.

• stdbuf -o0 tr '\n' '\r': Uses tr to exchange newlines with carriage returns. Stdbuf makes sure that the output is unbuffered; without the \n's, on a line buffered terminal, we'd see no output.

• echo: Outputs a final newline, so that the terminal prompt doesn't eat up the final line.

For the problem your edit proposes:

x=0; 
echo -e '\e[s'; 
tar -options -f dest source | while read line; do
      echo -en "\e[u" 
      if [ $x gt 0 ]; then echo -en "\e["$x"B"; fi;
      echo -en "\e[2K"
      echo -n $line | cut -b1-$(tput cols);
      let "x = ($x+1)%5";
done; echo;

Feel free to smush all that onto one line. This actually yields an alternative solution for the original problem:

echo -e '\e[s'; tar -options -f dest source | while read line; do echo -en "\e[u\e2K"; echo -n $line | cut -b1-$(tput cols); done; echo

which neatly relies on nothing except VT100 codes.