What command can filter control characters in Linux?

The command in Linux that can filter control characters is "col". The col command is a document editing command under Linux. Its full English name is "colation", which translates to "filtering". The col command has one main function, which can effectively filter out control characters in many description files. The syntax "col [ -bfx][-l]". The col command is equivalent to a standard input text filter. It reads the text content from the annotation input device and displays the content to the annotation output device.

The operating environment of this tutorial: linux7.3 system, Dell G3 computer.

The command in Linux that can filter control characters is "col".

Linux col command

The col command is a document editing command under Linux. Its full English name is "colation", which translates to " "Filter", the col command mainly has one function, which can effectively filter out control characters in many description files.

Description: The col command is equivalent to a standard input text filter. It reads the text content from the annotation input device and displays the content to the annotation output device.

In many UNIX documentation files, there are RLF control characters. When we use the shell special characters ">" and ">>" to output the contents of the description file into a plain text file, the control characters will become garbled characters. The col command can effectively filter out these control characters.

Syntax

col [-bfx][-l<缓冲区列数>]

Parameters:

• -b Filter out all control characters, including RLF and HRLF.

• -f Filters out RLF characters but allows HRLF characters to be rendered.

• -x Use multiple space characters to represent tab characters.

• -l The default memory buffer has 128 columns, and you can specify the buffer size yourself.

col command example

(1) Replace Tabs with spaces, usually 1 Tab is converted to 4 Space.

echo -e “123 456” | col -x

(2) Replace spaces with Tab, usually 4 spaces are converted into 1 Tab.

echo -e “123 456” | col -h

(3) Delete the control characters in the help document. Take the manual of col command as an example.

man col | col -b > man_col.txt

(4) The following uses the man command help document as an example to explain the use of the col command.

Save the help document of the man command as man_help, and use the -b parameter to filter all control characters. Use the following command in the terminal:

man man | col-b > man_help

Note: "|" is used to establish a pipeline and convert the output of the man command into the input data of the col command.

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