Bash-将标题添加到管道表命令 [英] Bash - Adding titles into to a piped table command

问题描述

我有一个简单的脚本，可以将students.txt文件的内容作为基本表输出到打印文件，然后显示出来.

I have a simple script to output the content of the file students.txt as a basic table to the print file, which is then displayed.

#!/bin/bash

cat students.txt | column -t -s',' | sort -u -k3 > print.txt
cat print.txt

输出如下:

Consoling  ST  DWC  0900
Scribing   RA  DWC  1000
Gloater    AU  DWC  1100
Crimp      DI  DWC  1200

，依此类推.但是，我还希望能够为每列添加标题，并使它们完美对齐，以及不进行排序.我尝试使用printf和echo，但是当通过管道将它们显示到命令中时，它们无法显示，并且无法通过在管道外部打印标题名称来正确对齐列.我正在寻找所需的输出看起来像这样:

and so on. However I also want to be able to add headings for each column and have them align perfectly, as well as not being sorted. I have tried to use printf and echo but when piped into the command they do not display and I cannot align the columns correctly by printing the heading names outside of the pipe. The desired output I am looking for would look like this:

Family Name  Initials  Interviewer Initials  Interview Time
Consoling    ST        DWC                   0900
Scribing     RA        DWC                   1000
Gloater      AU        DWC                   1100
Crimp        DI        DWC                   1200

我怎么能做到这一点?

推荐答案

有一个内衬:

cat <(echo "Family Name,Initials,Interviewer Initials,Interview Time") <(sort -u -k3 -t ',' students.txt) | column -s ',' -t > print.txt

这利用了流程替代.运行<()中的命令，其输出显示为文件名. cat连接两个文件"，其中包含echo(用于标题)和sort(用于对students.txt进行排序)的输出.

This makes use of Process Substitution. The command inside <() is run and it's output appears as a filename. cat concatenates the two "files", that contain the outputs of echo (for the headers) and sort (to sort your students.txt).

• sort与选项-t ','一起运行，以指定，"作为分隔符.
• column与选项-s ','一起运行，以指定，"作为分隔符.

• sort is run with option -t ',' to specifiy "," as the delimiter.
• column is run with option -s ',' to specify "," as the delimiter.

编辑(感谢@tripleee指出):

EDIT (thanks to @tripleee for pointing it out):

可以修改oneliner，这样就不需要 Process Substitution 和cat:

The oneliner can be modified, such that Process Substitution and cat isn't necessary:

{ echo "Family Name,Initials,Interviewer Initials,Interview Time"; sort -u -k3 -t ',' students.txt; } | column -s ',' -t > print.txt

echo和sort由{}分组，并在当前shell上下文中执行.重定向(通向column的管道)将应用于整个组.供参考:分组命令.

echo and sort are grouped by {} and are executed in the current shell context. The redirection (pipe to column) is applied to the entire group. For reference: Grouping Commands.

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