split(1): add '-c' to continue creating files

Currently, split(1) will clobber any existing output files:

$ split file; ls
xaa xab xac xad
$ split second-file; ls
xaa xab xac xad xae xaf

This patch adds a flag "-c" (mnemonic "create, don't overwrite" or
"continue where you left off"):

$ split file; ls
xaa xab xac xad
$ split -c second-file; ls
xaa xab xac xad xae xaf xag xah xai xaj

Reviewed by:	christos
Approved by:	kevans
Different Revision:	https://reviews.freebsd.org/D38553
This commit is contained in:
Jan Schaumann 2023-05-30 16:13:16 +03:00 committed by Christos Margiolis
parent c4f7198f47
commit ac17fc816e
2 changed files with 36 additions and 12 deletions

View file

@ -36,12 +36,12 @@
.Nd split a file into pieces
.Sh SYNOPSIS
.Nm
.Op Fl d
.Op Fl cd
.Op Fl l Ar line_count
.Op Fl a Ar suffix_length
.Op Ar file Op Ar prefix
.Nm
.Op Fl d
.Op Fl cd
.Fl b Ar byte_count Ns
.Oo
.Sm off
@ -51,12 +51,12 @@
.Op Fl a Ar suffix_length
.Op Ar file Op Ar prefix
.Nm
.Op Fl d
.Op Fl cd
.Fl n Ar chunk_count
.Op Fl a Ar suffix_length
.Op Ar file Op Ar prefix
.Nm
.Op Fl d
.Op Fl cd
.Fl p Ar pattern
.Op Fl a Ar suffix_length
.Op Ar file Op Ar prefix
@ -112,6 +112,9 @@ or
is appended to the number, the file is split into
.Ar byte_count
gigabyte pieces.
.It Fl c
Continue creating files and do not overwrite existing
output files.
.It Fl d
Use a numeric suffix instead of a alphabetic suffix.
.It Fl l Ar line_count
@ -163,6 +166,15 @@ argument is not specified, the file is split into lexically ordered
files named with the prefix
.Dq Li x
and with suffixes as above.
.Pp
By default,
.Nm
will overwrite any existing output files.
If the
.Fl c
flag is specified,
.Nm
will instead create files with names that do not already exist.
.Sh ENVIRONMENT
The
.Ev LANG , LC_ALL , LC_CTYPE

View file

@ -67,6 +67,7 @@ static const char sccsid[] = "@(#)split.c 8.2 (Berkeley) 4/16/94";
static off_t bytecnt; /* Byte count to split on. */
static off_t chunks = 0; /* Chunks count to split into. */
static bool clobber = true; /* Whether to overwrite existing output files. */
static long numlines; /* Line count to split on. */
static int file_open; /* If a file open. */
static int ifd = -1, ofd = -1; /* Input/output file descriptors. */
@ -93,7 +94,7 @@ main(int argc, char **argv)
setlocale(LC_ALL, "");
dflag = false;
while ((ch = getopt(argc, argv, "0123456789a:b:dl:n:p:")) != -1)
while ((ch = getopt(argc, argv, "0123456789a:b:cdl:n:p:")) != -1)
switch (ch) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
@ -125,6 +126,9 @@ main(int argc, char **argv)
if (error == -1)
errx(EX_USAGE, "%s: offset too large", optarg);
break;
case 'c': /* Continue, don't overwrite output files. */
clobber = false;
break;
case 'd': /* Decimal suffix */
dflag = true;
break;
@ -347,6 +351,10 @@ newfile(void)
static char *fpnt;
char beg, end;
int pattlen;
int flags = O_WRONLY | O_CREAT | O_TRUNC;
if (!clobber)
flags |= O_EXCL;
if (ofd == -1) {
if (fname[0] == '\0') {
@ -355,9 +363,10 @@ newfile(void)
} else {
fpnt = fname + strlen(fname);
}
ofd = fileno(stdout);
}
} else if (close(ofd) != 0)
err(1, "%s", fname);
again:
if (dflag) {
beg = '0';
end = '9';
@ -417,8 +426,11 @@ newfile(void)
fpnt[sufflen] = '\0';
++fnum;
if (!freopen(fname, "w", stdout))
if ((ofd = open(fname, flags, DEFFILEMODE)) < 0) {
if (!clobber && errno == EEXIST)
goto again;
err(EX_IOERR, "%s", fname);
}
file_open = 1;
}
@ -426,9 +438,9 @@ static void
usage(void)
{
(void)fprintf(stderr,
"usage: split [-d] [-l line_count] [-a suffix_length] [file [prefix]]\n"
" split [-d] -b byte_count[K|k|M|m|G|g] [-a suffix_length] [file [prefix]]\n"
" split [-d] -n chunk_count [-a suffix_length] [file [prefix]]\n"
" split [-d] -p pattern [-a suffix_length] [file [prefix]]\n");
"usage: split [-cd] [-l line_count] [-a suffix_length] [file [prefix]]\n"
" split [-cd] -b byte_count[K|k|M|m|G|g] [-a suffix_length] [file [prefix]]\n"
" split [-cd] -n chunk_count [-a suffix_length] [file [prefix]]\n"
" split [-cd] -p pattern [-a suffix_length] [file [prefix]]\n");
exit(EX_USAGE);
}