When debugging a shell script, a useful command is:
bash -x script-name
The deficiency of this is that "-x" causes all simple commands in your
startup files to be echoed as they are executed, and often this output
is a lot longer than the output from the commands in the script.
For a long time, I've wanted a variant of -x that only echoed the simple
commands after bash is done executing the startup files. I finally did
a test implementation, naming a new switch "-X". If it is set at the
end of the execution of the startup files, then bash sets "-x", which
causes subsequent simple commands to be echoed.
I named the new option "-X" as a mnemonic variant of "-x". Its long
name is "Xtrace", because I couldn't think of anything better. The code
changes are quite simple really.
Is this a useful idea? Is there a better way to get an effect like
this?
Dale
diff --git a/builtins/set.def b/builtins/set.def
index d2bba43..e71c58f 100644
--- a/builtins/set.def
+++ b/builtins/set.def
@@ -114,6 +114,7 @@ Options:
vi use a vi-style line editing interface
#endif /* READLINE */
xtrace same as -x
+ Xtrace same as -X
-p Turned on whenever the real and effective user ids do not match.
Disables processing of the $ENV file and importing of shell
functions. Turning this option off causes the effective uid and
@@ -122,6 +123,7 @@ Options:
-u Treat unset variables as an error when substituting.
-v Print shell input lines as they are read.
-x Print commands and their arguments as they are executed.
+ -X Set -x after startup files are executed.
#if defined (BRACE_EXPANSION)
-B the shell will perform brace expansion
#endif /* BRACE_EXPANSION */
@@ -231,6 +233,7 @@ const struct {
{ "vi", '\0', (int *)NULL, set_edit_mode, get_edit_mode },
#endif
{ "xtrace", 'x', (int *)NULL, (setopt_set_func_t *)NULL,
(setopt_get_func_t *)NULL },
+ { "Xtrace", 'X', (int *)NULL, (setopt_set_func_t *)NULL,
(setopt_get_func_t *)NULL },
{(char *)NULL, 0 , (int *)NULL, (setopt_set_func_t *)NULL,
(setopt_get_func_t *)NULL },
};
diff --git a/flags.c b/flags.c
index 6e20841..0828f78 100644
--- a/flags.c
+++ b/flags.c
@@ -159,6 +159,9 @@ int error_trace_mode = 0;
with a 0 status, the status of the pipeline is 0. */
int pipefail_opt = 0;
+/* Non-zero means set -x after startup files are executed. */
+int echo_commands_after_startup = 0;
+
/* **************************************************************** */
/* */
/* The Flags ALIST. */
@@ -187,7 +190,7 @@ const struct flags_alist shell_flags[] = {
{ 't', &just_one_command },
{ 'u', &unbound_vars_is_error },
{ 'v', &verbose_flag },
- { 'x', &echo_command_at_execute },
+ { 'x', &echo_command_at_execute },
/* New flags that control non-standard things. */
#if 0
@@ -204,6 +207,7 @@ const struct flags_alist shell_flags[] = {
{ 'I', &no_invisible_vars },
{ 'P', &no_symbolic_links },
{ 'T', &function_trace_mode },
+ { 'X', &echo_commands_after_startup },
{0, (int *)NULL}
};
diff --git a/flags.h b/flags.h
index fdbf7f9..3b6fa8c 100644
--- a/flags.h
+++ b/flags.h
@@ -48,7 +48,8 @@ extern int
echo_command_at_execute, no_invisible_vars, noclobber,
hashing_enabled, forced_interactive, privileged_mode, jobs_m_flag,
asynchronous_notification, interactive_comments, no_symbolic_links,
- function_trace_mode, error_trace_mode, pipefail_opt;
+ function_trace_mode, error_trace_mode, pipefail_opt,
+ echo_commands_after_startup;
/* -c, -s invocation options -- not really flags, but they show up in $- */
extern int want_pending_command, read_from_stdin;
diff --git a/shell.c b/shell.c
index a2b2a55..4c40cd4 100644
--- a/shell.c
+++ b/shell.c
@@ -731,6 +731,10 @@ main (argc, argv, env)
start_debugger ();
#if defined (ONESHOT)
+ if (echo_commands_after_startup) {
+ set_minus_o_option (FLAG_ON, "xtrace");
+ set_shellopts ();
+ }
executing = 1;
run_one_command (command_execution_string);
exit_shell (last_command_exit_value);
@@ -791,6 +795,11 @@ main (argc, argv, env)
read_and_execute:
#endif /* !ONESHOT */
+ if (echo_commands_after_startup) {
+ set_minus_o_option (FLAG_ON, "xtrace");
+ set_shellopts ();
+ }
+
shell_initialized = 1;
if (pretty_print_mode && interactive_shell)
