common/*: update pages of some POSIX special built-in utilities (#11956)

* exec, export, readonly, set, shift, trap: replace command descriptions

* exec, exit, export, readonly, set, shift, trap, exec, export: replace example descriptions

* exec, trap: replace "More information" links

* trap: remove prefix "SIG" from some command arguments

Although POSIX allows implementations to specify signal names without
the prefix "SIG", I will choose the most portable form.

* export: replace term

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

* set: replace term

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

* export: replace term

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

* export: replace term

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

* exec: replace Open Group link

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

* exit: replace Open Group link

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

* export: replace Open Group link

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

* readonly: replace Open Group link

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

* set: replace Open Group link

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

* shift: replace Open Group link

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

* trap: replace Open Group link

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

* exec: explain environment of child process

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

---------

Co-authored-by: Vitor Henrique <87824454+vitorhcl@users.noreply.github.com>

pages/common/exec.md

@@ -1,8 +1,8 @@
 # exec
 
-> Replace the current process with another process.
-> More information: <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#exec>.
+> Execute a command without creating a child process.
+> More information: <https://manned.org/exec.1posix>.
 
-- Replace with the specified command using the current environment variables:
+- Execute a specific command using the current environment variables:
 
 `exec {{command -with -flags}}`

pages/common/exit.md

@@ -1,12 +1,12 @@
 # exit
 
 > Exit the shell.
-> More information: <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#exit>.
+> More information: <https://manned.org/exit.1posix>.
 
-- Exit the shell with the exit code of the last command executed:
+- Exit with the exit status of the most recently executed command:
 
 `exit`
 
-- Exit the shell with the specified exit code:
+- Exit with a specific exit status:
 
 `exit {{exit_code}}`

pages/common/export.md

@@ -1,12 +1,12 @@
 # export
 
-> Command to mark shell variables in the current environment to be exported with any newly forked child processes.
-> More information: <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#export>.
+> Export shell variables to child processes.
+> More information: <https://manned.org/export.1posix>.
 
-- Set a new environment variable:
+- Set an environment variable:
 
 `export {{VARIABLE}}={{value}}`
 
-- Append something to the PATH variable:
+- Append a pathname to the environment variable `PATH`:
 
 `export PATH=$PATH:{{path/to/append}}`

pages/common/readonly.md

@@ -1,10 +1,9 @@
 # readonly
 
-> 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://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#readonly>.
+> Set read-only shell variables.
+> More information: <https://manned.org/readonly.1posix>.
 
-- Create a read-only variable:
+- Set a read-only variable:
 
 `readonly {{variable_name}}={{value}}`
 

pages/common/set.md

@@ -1,24 +1,24 @@
 # set
 
-> Display, set or unset values of shell attributes and positional parameters.
-> More information: <https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#set>.
+> Toggle shell options or set the values of positional parameters.
+> More information: <https://manned.org/set.1posix>.
 
 - Display the names and values of shell variables:
 
 `set`
 
-- Mark variables that are modified or created for export:
+- Export newly initialized variables to child processes:
 
 `set -a`
 
-- Notify of job termination immediately:
+- Write formatted messages to `stderr` when jobs finish:
 
 `set -b`
 
-- Set various options, e.g. enable `vi` style line editing:
+- Write and edit text in the command line with `vi`-like keybindings (e.g. `yy`):
 
 `set -o {{vi}}`
 
-- Set the shell to exit as soon as the first error is encountered (mostly used in scripts):
+- Exit the shell when (some) commands fail:
 
 `set -e`

pages/common/shift.md

@@ -1,12 +1,12 @@
 # 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://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#shift>.
+> Move positional parameters.
+> More information: <https://manned.org/shift.1posix>.
 
-- Move arguments by one place dropping the first argument:
+- Remove the first positional parameter:
 
 `shift`
 
-- Move arguments by N places dropping the first N arguments:
+- Remove the first `N` positional parameters:
 
 `shift {{N}}`

pages/common/trap.md

@@ -1,17 +1,16 @@
 # 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://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap>.
+> Execute a command upon an event.
+> More information: <https://manned.org/trap.1posix>.
 
-- List active traps for the current shell:
+- List the commands and the names of the expected events:
 
 `trap`
 
-- Set a trap to execute commands when one or more signals are detected:
+- Execute a command when a signal is received:
 
-`trap 'echo "Caught signal {{SIGHUP}}"' {{SIGHUP}}`
+`trap 'echo "Caught signal {{SIGHUP}}"' {{HUP}}`
 
-- Remove active traps:
+- Remove commands:
 
-`trap - {{SIGHUP}} {{SIGINT}}`
+`trap - {{HUP}} {{INT}}`

pages/linux/exec.md

@@ -1,20 +1,20 @@
 # exec
 
-> Replace the current process with another process.
-> More information: <https://linuxcommand.org/lc3_man_pages/exech.html>.
+> Execute a command without creating a child process.
+> More information: <https://www.gnu.org/software/bash/manual/bash.html#index-exec>.
 
-- Replace with the specified command using the current environment variables:
+- Execute a specific command:
 
 `exec {{command -with -flags}}`
 
-- Replace with the specified command, clearing environment variables:
+- Execute a command with a (mostly) empty environment:
 
 `exec -c {{command -with -flags}}`
 
-- Replace with the specified command and login using the default shell:
+- Execute a command as a login shell:
 
 `exec -l {{command -with -flags}}`
 
-- Replace with the specified command and change the process name:
+- Execute a command with a different name:
 
-`exec -a {{process_name}} {{command -with -flags}}`
+`exec -a {{name}} {{command -with -flags}}`

pages/linux/export.md

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

pages/linux/trap.md

@@ -1,21 +1,20 @@
 # 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>.
+> Execute a command upon an event.
+> More information: <https://www.gnu.org/software/bash/manual/bash.html#index-trap>.
 
-- List available signals to set traps for:
+- List the available event names (e.g. `SIGWINCH`):
 
 `trap -l`
 
-- List active traps for the current shell:
+- List the commands and the names of the expected events:
 
 `trap -p`
 
-- Set a trap to execute commands when one or more signals are detected:
+- Execute a command when a signal is received:
 
 `trap 'echo "Caught signal {{SIGHUP}}"' {{SIGHUP}}`
 
-- Remove active traps:
+- Remove commands:
 
 `trap - {{SIGHUP}} {{SIGINT}}`