how to using Linux pipe command output another command's help content to a file

how to using Linux pipe command output another command's help content to a file

Linux tee > >>

gcc help

$ gcc --help
# ❌ ???
$ gcc --help | echo > gcc-help.md

# output help to a file ✅
$ gcc --help > gcc-help.md

> && >>

# > overwrite file
$ gcc --help > gcc-help.md

# >> append data
$ gcc --help >> gcc-help.md

total 10 ways

         || visible in terminal ||   visible in file   || existing
  Syntax  ||  StdOut  |  StdErr  ||  StdOut  |  StdErr  ||   file   
==========++==========+==========++==========+==========++===========
    >     ||    no    |   yes    ||   yes    |    no    || overwrite
    >>    ||    no    |   yes    ||   yes    |    no    ||  append
          ||          |          ||          |          ||
   2>     ||   yes    |    no    ||    no    |   yes    || overwrite
   2>>    ||   yes    |    no    ||    no    |   yes    ||  append
          ||          |          ||          |          ||
   &>     ||    no    |    no    ||   yes    |   yes    || overwrite
   &>>    ||    no    |    no    ||   yes    |   yes    ||  append
          ||          |          ||          |          ||
 | tee    ||   yes    |   yes    ||   yes    |    no    || overwrite
 | tee -a ||   yes    |   yes    ||   yes    |    no    ||  append
          ||          |          ||          |          ||
 n.e. (*) ||   yes    |   yes    ||    no    |   yes    || overwrite
 n.e. (*) ||   yes    |   yes    ||    no    |   yes    ||  append
          ||          |          ||          |          ||
|& tee    ||   yes    |   yes    ||   yes    |   yes    || overwrite
|& tee -a ||   yes    |   yes    ||   yes    |   yes    ||  append

tee

# output help to a file ✅
$ gcc --help | tee gcc-help.txt

# > overwrite file
$ gcc --help > gcc-help.txt
# >> append data
$ gcc --help >> gcc-help.txt

refs

https://askubuntu.com/questions/420981/how-do-i-save-terminal-output-to-a-file

https://en.wikipedia.org/wiki/Standard_streams#Standard_error_.28stderr.29

https://askubuntu.com/questions/38126/how-to-redirect-output-to-screen-as-well-as-a-file

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