usage: strptime timestamp fmt
Most other userspace implementations allow in date(1) the parsing
of dates. That way, one can use a date string, and manipulate it
in scripts. However, the current date(1) implementation only accepts
Unix epochs to describe date and time. Rather than patching date(1)
to add in more and more features, I believe having a separate tool
that is more specialized is closer to the Unix philosophy.
---
.gitignore | 1 +
Makefile | 1 +
README | 1 +
strptime.1 | 22 ++++++++++++++++++++++
strptime.c | 39 +++++++++++++++++++++++++++++++++++++++
5 files changed, 64 insertions(+)
create mode 100644 strptime.1
create mode 100644 strptime.c
diff --git a/.gitignore b/.gitignore
index daa7189..e591886 100644
--- a/.gitignore
+++ b/.gitignore
@@ -76,6 +76,7 @@
/split
/sponge
/strings
+/strptime
/sync
/tac
/tail
diff --git a/Makefile b/Makefile
index 8a4c1ef..55e00d9 100644
--- a/Makefile
+++ b/Makefile
@@ -165,6 +165,7 @@ BIN =\
split\
sponge\
strings\
+ strptime\
sync\
tac\
tail\
diff --git a/README b/README
index f16eab8..91a60f9 100644
--- a/README
+++ b/README
@@ -117,6 +117,7 @@ The following tools are implemented:
0=*|o split .
0=*|x sponge .
0#*|o strings .
+0=* x strptime .
0=*|x sync .
0=* x tac .
0=*|o tail .
diff --git a/strptime.1 b/strptime.1
new file mode 100644
index 0000000..8f91238
--- /dev/null
+++ b/strptime.1
@@ -0,0 +1,22 @@
+.Dd 2024-02-25
+.Dt STRPTIME 1
+.Os sbase
+.Sh NAME
+.Nm strptime
+.Nd parse date and time string
+.Sh SYNOPSIS
+.Nm
+.Ar time format
+.Sh DESCRIPTION
+.Nm
+parses
+.Ar time
+according to
+.Ar format
+(see
+.Xr strptime 3 ) .
+and prints it as the number of seconds since the
+Unix epoch.
+.Sh SEE ALSO
+.Xr date 1 ,
+.Xr strptime 3
diff --git a/strptime.c b/strptime.c
new file mode 100644
index 0000000..9d65219
--- /dev/null
+++ b/strptime.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <time.h>
+
+#include "util.h"
+
+static void
+usage(void)
+{
+ eprintf("usage: %s format time\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+ struct tm *tm;
+ time_t curtime;
+
+ ARGBEGIN {
+ default:
+ usage();
+ } ARGEND
+
+ /* This make mktime(3) guess whether Daylight Saving Time is in effect.
+ * If not specified, the output is non-deterministic, considering that
+ * tm is initially random */
+ curtime = time(NULL);
+ tm = localtime(&curtime);
+ tm->tm_isdst = -1;
+
+ if (argc != 2)
+ usage();
+ if (strptime(argv[1], argv[0], tm) == NULL)
+ eprintf("unable to parse\n");
+ if ((curtime = mktime(tm)) == -1)
+ eprintf("mktime:");
+
+ printf("%ld\n", curtime);
+ return 0;
+}
--
2.44.0
