This patch implements prompting for user input before executing
commands. Input is read from /dev/tty as per posix 2013 spec.
---
README | 2 +-
xargs.1 | 6 +++++-
xargs.c | 28 +++++++++++++++++++++++++---
3 files changed, 31 insertions(+), 5 deletions(-)
diff --git a/README b/README
index 68a921c..e8b16b0 100644
--- a/README
+++ b/README
@@ -99,7 +99,7 @@ The following tools are implemented:
#*|o wc .
=*|x which .
=*|x whoami .
-=*|o xargs (-p)
+=*|o xargs .
=*|x yes .
The complement of sbase is ubase[1] which is Linux-specific and
diff --git a/xargs.1 b/xargs.1
index 47cc194..1015756 100644
--- a/xargs.1
+++ b/xargs.1
@@ -6,7 +6,7 @@
.Nd construct argument lists and execute command
.Sh SYNOPSIS
.Nm
-.Op Fl rtx
+.Op Fl prtx
.Op Fl E Ar eofstr
.Op Fl n Ar num
.Op Fl s Ar num
@@ -36,6 +36,10 @@ newlines, may be escaped by a backslash.
Use at most
.Ar num
arguments per command line.
+.It Fl p
+Prompt before running each command. Run the command only if the response
+starts with 'y' or 'Y'. Implies
+.Fl t .
.It Fl r
Do not run the command if there are no arguments. Normally the command is
executed at least once even if there are no arguments.
diff --git a/xargs.c b/xargs.c
index 0d5dd53..5b3d214 100644
--- a/xargs.c
+++ b/xargs.c
@@ -26,7 +26,7 @@ static size_t argbsz;
static size_t argbpos;
static size_t maxargs = 0;
static int nerrors = 0;
-static int rflag = 0, nflag = 0, tflag = 0, xflag = 0;
+static int nflag = 0, pflag = 0, rflag = 0, tflag = 0, xflag = 0;
static char *argb;
static char *cmd[NARGS];
static char *eofstr;
@@ -162,15 +162,34 @@ spawn(void)
int savederrno;
int first = 1;
char **p;
+ FILE *tty;
+ int ch, savedch;
- if (tflag) {
+ if (pflag || tflag) {
for (p = cmd; *p; p++) {
if (!first)
fputc(' ', stderr);
fputs(*p, stderr);
first = 0;
}
+ }
+
+ if (!pflag && tflag)
fputc('\n', stderr);
+
+ if (pflag) {
+ fputs(" ?...", stderr);
+
+ tty = fopen("/dev/tty", "r");
+ if (!tty)
+ return;
+ ch = savedch = fgetc(tty);
+ while (ch != EOF && ch != '\n')
+ ch = getc(tty);
+ fclose(tty);
+
+ if (savedch != 'y' && savedch != 'Y')
+ return;
}
switch (fork()) {
@@ -188,7 +207,7 @@ spawn(void)
static void
usage(void)
{
- eprintf("usage: %s [-rtx] [-E eofstr] [-n num] [-s num] "
+ eprintf("usage: %s [-prtx] [-E eofstr] [-n num] [-s num] "
"[cmd [arg ...]]\n", argv0);
}
@@ -210,6 +229,9 @@ main(int argc, char *argv[])
nflag = 1;
maxargs = estrtonum(EARGF(usage()), 1, MIN(SIZE_MAX,
LLONG_MAX));
break;
+ case 'p':
+ pflag = 1;
+ break;
case 'r':
rflag = 1;
break;
--
2.1.4
