common/*: update pages of POSIX special Built-In utilities (#11858)

* eval, exec, exit, export, readonly, set, shift, trap: use Open Group links

* exec, export, trap: split Linux and POSIX

pages/common/eval.md

@@ -1,7 +1,7 @@
 # eval
 
 > Execute arguments as a single command in the current shell and return its result.
-> More information: <https://manned.org/eval>.
+> More information: <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#eval>.
 
 - Call `echo` with the "foo" argument:
 

pages/common/exec.md

@@ -1,20 +1,8 @@
 # exec
 
 > Replace the current process with another process.
-> More information: <https://linuxcommand.org/lc3_man_pages/exech.html>.
+> More information: <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#exec>.
 
 - Replace with the specified command using the current environment variables:
 
 `exec {{command -with -flags}}`
-
-- Replace with the specified command, clearing environment variables:
-
-`exec -c {{command -with -flags}}`
-
-- Replace with the specified command and login using the default shell:
-
-`exec -l {{command -with -flags}}`
-
-- Replace with the specified command and change the process name:
-
-`exec -a {{process_name}} {{command -with -flags}}`

pages/common/exit.md

@@ -1,7 +1,7 @@
 # exit
 
 > Exit the shell.
-> More information: <https://manned.org/exit>.
+> More information: <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#exit>.
 
 - Exit the shell with the exit code of the last command executed:
 

pages/common/export.md

@@ -1,20 +1,12 @@
 # export
 
 > Command to mark shell variables in the current environment to be exported with any newly forked child processes.
-> More information: <https://www.gnu.org/software/bash/manual/bash.html#index-export>.
+> More information: <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#export>.
 
 - Set a new environment variable:
 
 `export {{VARIABLE}}={{value}}`
 
-- Remove an environment variable:
-
-`export -n {{VARIABLE}}`
-
-- Mark a shell function for export:
-
-`export -f {{FUNCTION_NAME}}`
-
 - Append something to the PATH variable:
 
 `export PATH=$PATH:{{path/to/append}}`

pages/common/readonly.md

@@ -2,7 +2,7 @@
 
 > Create or modify read-only variables within a shell script, preventing the variable from being changed by subsequent commands.
 > This is useful when you want to ensure that a variable retains a constant value throughout the execution of a script.
-> More information: <https://manned.org/readonly.1p>.
+> More information: <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#readonly>.
 
 - Create a read-only variable:
 

pages/common/set.md

@@ -1,7 +1,7 @@
 # set
 
 > Display, set or unset values of shell attributes and positional parameters.
-> More information: <https://manned.org/set>.
+> More information: <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set>.
 
 - Display the names and values of shell variables:
 

pages/common/shift.md

@@ -1,7 +1,7 @@
 # shift
 
 > Shell built-in command that shifts the arguments passed to the calling function or script by a specified number of places.
-> More information: <https://www.gnu.org/software/bash/manual/bash.html#index-shift>.
+> More information: <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#shift>.
 
 - Move arguments by one place dropping the first argument:
 

pages/common/trap.md

@@ -2,15 +2,11 @@
 
 > Automatically execute commands after receiving signals by processes or the operating system.
 > Can be used to perform cleanups for interruptions by the user or other actions.
-> More information: <https://manned.org/trap>.
-
-- List available signals to set traps for:
-
-`trap -l`
+> More information: <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap>.
 
 - List active traps for the current shell:
 
-`trap -p`
+`trap`
 
 - Set a trap to execute commands when one or more signals are detected:
 

pages/linux/exec.md

@@ -0,0 +1,20 @@
+# exec
+
+> Replace the current process with another process.
+> More information: <https://linuxcommand.org/lc3_man_pages/exech.html>.
+
+- Replace with the specified command using the current environment variables:
+
+`exec {{command -with -flags}}`
+
+- Replace with the specified command, clearing environment variables:
+
+`exec -c {{command -with -flags}}`
+
+- Replace with the specified command and login using the default shell:
+
+`exec -l {{command -with -flags}}`
+
+- Replace with the specified command and change the process name:
+
+`exec -a {{process_name}} {{command -with -flags}}`

pages/linux/export.md

@@ -0,0 +1,20 @@
+# export
+
+> Command to mark shell variables in the current environment to be exported with any newly forked child processes.
+> More information: <https://www.gnu.org/software/bash/manual/bash.html#index-export>.
+
+- Set a new environment variable:
+
+`export {{VARIABLE}}={{value}}`
+
+- Remove an environment variable:
+
+`export -n {{VARIABLE}}`
+
+- Mark a shell function for export:
+
+`export -f {{FUNCTION_NAME}}`
+
+- Append something to the PATH variable:
+
+`export PATH=$PATH:{{path/to/append}}`

pages/linux/trap.md

@@ -0,0 +1,21 @@
+# trap
+
+> Automatically execute commands after receiving signals by processes or the operating system.
+> Can be used to perform cleanups for interruptions by the user or other actions.
+> More information: <https://manned.org/trap>.
+
+- List available signals to set traps for:
+
+`trap -l`
+
+- List active traps for the current shell:
+
+`trap -p`
+
+- Set a trap to execute commands when one or more signals are detected:
+
+`trap 'echo "Caught signal {{SIGHUP}}"' {{SIGHUP}}`
+
+- Remove active traps:
+
+`trap - {{SIGHUP}} {{SIGINT}}`