compgen, eval, export, file: move to common (#6508)

pages.zh/common/compgen.md

@@ -1,7 +1,7 @@
 # compgen
 
 > 用于在 bash 中自动完成的内置命令，按两次 tab 键即可调用该命令。
-> 更多信息：<https://www.cyberciti.biz/open-source/command-line-hacks/compgen-linux-command/>.
+> 更多信息：<https://www.gnu.org/software/bash/manual/bash.html#index-compgen>.
 
 - 显示所有可以执行的命令：
 

pages.zh/common/export.md

@@ -1,7 +1,7 @@
 # export
 
 > 命令为当前 shell 中的子进程进行环境变量设置。
-> 更多信息：<https://ss64.com/osx/export.html>.
+> 更多信息：<https://www.gnu.org/software/bash/manual/bash.html#index-export>.
 
 - 设置为新的环境变量：
 

pages/osx/compgen.md

@@ -1,24 +0,0 @@
-# compgen
-
-> A built-in command for auto-completion in Bash, which is called on pressing TAB key twice.
-> More information: <https://www.cyberciti.biz/open-source/command-line-hacks/compgen-linux-command/>.
-
-- List all commands that you could run:
-
-`compgen -c`
-
-- List all aliases:
-
-`compgen -a`
-
-- List all functions that you could run:
-
-`compgen -A function`
-
-- Show shell reserved keywords:
-
-`compgen -k`
-
-- See all available commands/aliases starting with 'ls':
-
-`compgen -ac {{ls}}`

pages/osx/eval.md

@@ -1,12 +0,0 @@
-# eval
-
-> Execute arguments as a single command in the current shell and return its result.
-> More information: <https://ss64.com/osx/eval.html>.
-
-- Call `echo` with the "foo" argument:
-
-`eval "{{echo foo}}"`
-
-- Set a variable in the current shell:
-
-`eval "{{foo=bar}}"`

pages/osx/export.md

@@ -1,16 +0,0 @@
-# export
-
-> Command to mark shell variables in the current environment to be exported with any newly forked child processes.
-> More information: <https://ss64.com/osx/export.html>.
-
-- Set a new environment variable:
-
-`export {{VARIABLE}}={{value}}`
-
-- Remove an environment variable:
-
-`export -n {{VARIABLE}}`
-
-- Append something to the PATH variable:
-
-`export PATH=$PATH:{{path/to/append}}`

pages/osx/file.md

@@ -1,24 +0,0 @@
-# file
-
-> Determine file type.
-> More information: <https://github.com/file/file>.
-
-- Give a description of the type of the specified file. Works fine for files with no file extension:
-
-`file {{filename}}`
-
-- Look inside a zipped file and determine the file type(s) inside:
-
-`file -z {{foo.zip}}`
-
-- Allow file to work with special or device files:
-
-`file -s {{filename}}`
-
-- Don't stop at first file type match; keep going until the end of the file:
-
-`file -k {{filename}}`
-
-- Determine the mime encoding type of a file:
-
-`file -I {{filename}}`