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col-过滤控制字符.md

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col command

In many UNIX documentation files, there are RLF control characters. When we output the contents of the documentation file to a plain text file, the control characters become garbled. The col command effectively filters out these control characters.

Syntax

col [options]

Arguments

  • -b, --no-backspaces: Filter out all control characters, including RLF and HRLF.
  • -f, --fine: Allow half-line breaks, usually characters printed at the half-line boundary will be printed on the next line, filters out RLF characters, but allows HRLF characters to be displayed.
  • -p, --pass: Pass through unknown control sequences, usually col filters out any control sequences from the input other than those it recognizes and interprets itself.
  • -h, --tabs: Convert spaces to tabs, this is the default setting.
  • -x, --spaces: Convert tabs to spaces.
  • -l, --lines NUM: Buffer at least num lines in memory, by default buffers 128 lines.
  • -V, --version: Output version information.
  • -H, --help: Output help information.

Examples

Filter out reverse line feed RLF from the help documentation of col and save it to col.txt.

col --help | col > col.txt

Filter out control characters from the help documentation of col and save it to col.txt.

col --help | col -b > col.txt

Convert tabs to spaces in the help documentation of col and save it to col.txt.

col --help | col -x > col.txt

Daily question

https://github.com/WindrunnerMax/EveryDay

Reference

https://www.computerhope.com/unix/ucol.htm
https://www.runoob.com/linux/linux-comm-col.html
https://www.geeksforgeeks.org/col-command-in-linux-with-examples/