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authorRob Landley <rob@landley.net>2012-02-28 00:29:52 -0600
committerRob Landley <rob@landley.net>2012-02-28 00:29:52 -0600
commitb73d8e3c2d3b606295453940e602d173924cd380 (patch)
treee27f1493aaf74291e83e9f7bfe146c57959855d7 /toys/tail.c
parentf793d5347f08bdb742e8ad8a2cc5a7d30e6bd623 (diff)
downloadtoybox-b73d8e3c2d3b606295453940e602d173924cd380.tar.gz
Add "-" type to optargs and teach tail.c to use it. Tighten up help text, use xzalloc() and xputc() as appropriate.
Diffstat (limited to 'toys/tail.c')
-rw-r--r--toys/tail.c46
1 files changed, 11 insertions, 35 deletions
diff --git a/toys/tail.c b/toys/tail.c
index 5ae295b8..b992cd16 100644
--- a/toys/tail.c
+++ b/toys/tail.c
@@ -6,38 +6,28 @@
*
* See http://www.opengroup.org/onlinepubs/009695399/utilities/tail.html
-USE_TAIL(NEWTOY(tail, "c:fn:", TOYFLAG_BIN))
+USE_TAIL(NEWTOY(tail, "c-|fn-|", TOYFLAG_BIN))
config TAIL
bool "tail"
default n
help
- usage: tail [-n number] [-c number] [-f] [file...]
+ usage: tail [-n|c number] [-f] [file...]
Copy last lines from files to stdout. If no files listed, copy from
stdin. Filename "-" is a synonym for stdin.
- -n Line offset to start copying from. The number may be signed.
- When negative, the line offset is counted from the end of the
- file. When positive, the offset is counted from the beginning.
- When the sign is omitted, the offset is counted from the end of
- the file. Defaults to -10.
-
- -c Byte offset to start copying from. As above, may be a positive
- or negative signed number.
-
- -f Continue reading input after reaching the last line of input.
- This option is ignored if the input file is not a regular file
- or the given file is a FIFO.
+ -n output the last X lines (default 10), +X counts from start.
+ -c output the last X bytes, +X counts from start
+ -f follow file, waiting for more data to be appended
*/
#include "toys.h"
DEFINE_GLOBALS(
- char *lines_str;
- char *bytes_str;
long lines;
long bytes;
+
int file_no;
)
@@ -128,8 +118,7 @@ static void print_last_lines(int fd, long lines)
for (;;) {
// read from input and append to buffer list
- cur = xmalloc(sizeof(struct line_list));
- memset(cur, 0, sizeof(struct line_list));
+ cur = xzalloc(sizeof(struct line_list));
cur->data = xmalloc(size);
cur->len = readall(fd, cur->data, size);
@@ -170,32 +159,19 @@ static void do_tail(int fd, char *name)
if (toys.optc > 1) {
// print an extra newline for all but the first file
- if (TT.file_no++) xprintf("\n");
+ if (TT.file_no++) xputc('\n');
xprintf("==> %s <==\n", name);
- xflush();
}
if (lines > 0 || bytes > 0) print_after_offset(fd, bytes, lines);
else if (bytes < 0) print_last_bytes(fd, bytes * -1);
- else if (lines < 0) print_last_lines(fd, lines * -1);
-}
-
-long atolx_default_negative(char *str)
-{
- long val = atolx(str);
- return str[0] != '+' && str[0] != '-' ? val * -1 : val;
+ else print_last_lines(fd, lines * -1);
}
void tail_main(void)
{
- // if option -c or -n has no sign then we make it negative
- if (toys.optflags & FLAG_c)
- TT.bytes = atolx_default_negative(TT.bytes_str);
-
- if (toys.optflags & FLAG_n)
- TT.lines = atolx_default_negative(TT.lines_str);
- else
- TT.lines = -10;
+ // if nothing specified, default -n to -10
+ if (!(toys.optflags&(FLAG_n|FLAG_c))) TT.lines = -10;
loopfiles(toys.optargs, do_tail);
}