Add seq -w, suggested by izabera.

tests/seq.test

@@ -23,8 +23,14 @@ testing "seq count by .3" "seq 3 .3 4" "3\n3.3\n3.6\n3.9\n" "" ""
 testing "seq count by -.9" "seq .7 -.9 -2.2" "0.7\n-0.2\n-1.1\n-2\n" "" ""
 testing "seq count by zero" "seq 4 0 8 | head -n 10" "" "" ""
 testing "seq separator -" "seq -s - 1 3" "1-2-3\n" "" ""
-testing "seq format string" 'seq -f %+01g -10 5 10' "-10\n-5\n+0\n+5\n+10\n" "" ""
+testing "seq format string" 'seq -f %+01g -10 5 10' "-10\n-5\n+0\n+5\n+10\n" \
+ "" ""
 testing "seq separator and format string" "seq -f \%03g -s \; 5 -1 0" "005;004;003;002;001;000\n" "" ""
+testing "seq padding" "seq -s, -w -2 19 120" "-02,017,036,055,074,093,112\n" \
+ "" ""
+testing "seq padding" "seq -s, -w -2 3 12" "-2,01,04,07,10\n" "" ""
+testing "seq padding" "seq -s, -w -2.2 3.3 12" "-2.2,01.1,04.4,07.7,11.0\n" \
+ "" ""
 
 # Test -f format filtering
 for i in %f %e %g "boo %f yah" "% f" %-1.2f %+-f "%+ - f" %.2f %3.f "%'.2f" \

toys/lsb/seq.c

@@ -4,21 +4,22 @@
  *
  * http:https://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/seq.html
 
-USE_SEQ(NEWTOY(seq, "<1>3?f:s:", TOYFLAG_USR|TOYFLAG_BIN))
+USE_SEQ(NEWTOY(seq, "<1>3?f:s:w[!fw]", TOYFLAG_USR|TOYFLAG_BIN))
 
 config SEQ
  bool "seq"
  depends on TOYBOX_FLOAT
  default y
  help
- usage: seq [-f fmt_str] [-s sep_str] [first] [increment] last
+ usage: seq [-w|-f fmt_str] [-s sep_str] [first] [increment] last
 
  Count from first to last, by increment. Omitted arguments default
  to 1. Two arguments are used as first and last. Arguments can be
  negative or floating point.
 
  -f Use fmt_str as a printf-style floating point format string
  -s Use sep_str as separator, default is a newline character
+ -w Pad to equal width with leading zeroes.
 */
 
 #define FOR_seq
@@ -44,8 +45,7 @@ static void insanitize(char *f)
 void seq_main(void)
 {
  double first, increment, last, dd;
- char *sep_str = "\n";
- char *fmt_str = "%g";
+ char *sep_str = "\n", *fmt_str = "%g";
  int output = 0;
 
  // Parse command line arguments, with appropriate defaults.
@@ -57,6 +57,25 @@ void seq_main(void)
  default: last = atof(toys.optargs[toys.optc-1]);
  }
 
+ // Pad to largest width
+ if (toys.optflags & FLAG_w) {
+ char *s;
+ int i, len, dot, left = 0, right = 0;
+
+ for (i=0; i<3; i++) {
+ dd = (double []){first, increment, last}[i];
+
+ len = sprintf(toybuf, "%g", dd);
+ if ((s = strchr(toybuf, '.'))) {
+ dot = s-toybuf;
+ if (left<dot) left = dot;
+ dot = len-dot-1;
+ if (right<dot) right = dot;
+ } else if (len>left) left = len;
+ }
+
+ sprintf(fmt_str = toybuf, "%%0%d.%df", left+right+!!right, right);
+ }
  if (toys.optflags & FLAG_f) insanitize(fmt_str = TT.fmt);
  if (toys.optflags & FLAG_s) sep_str = TT.sep;