commit: 80fc05ca12019b1145e407b921cd03cf6162c471
parent b1ce552adedbaa4b74341a1635fe12111aabbee9
Author: Haelwenn (lanodan) Monnier <contact@hacktivis.me>
Date: Wed, 26 Mar 2025 14:35:22 +0100
cmd/echo: support -e and -E options for toggling escape codes support
Diffstat:
| M | cmd/echo.1 | 39 | ++++++++++++++++++++++++++++++++++----- |
| M | cmd/echo.c | 116 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---- |
| M | test-cmd/echo.sh | 41 | +++++++++++++++++++++++++++++++++++++++-- |
3 files changed, 184 insertions(+), 12 deletions(-)
diff --git a/cmd/echo.1 b/cmd/echo.1
@@ -9,7 +9,7 @@
.Nd write arguments to standard output
.Sh SYNOPSIS
.Nm
-.Op Fl n
+.Op Fl Een
.Op Ar string...
.Sh DESCRIPTION
.Nm
@@ -28,16 +28,45 @@ operand, which generally terminates option processing, is treated as part of
.Bl -tag -width Ds
.It Fl n
Do not print the trailing newline character.
+.It Fl E
+Toggle off the support for escape codes. (default)
+.It Fl e
+Toggle on support for the following escape codes:
+.Bl -tag -compact -width _a
+.It \ea
+Write an <alert>.
+.It \eb
+Write a <backspace>.
+.It \ec
+Clear the rest of the output, including the trailing newline.
+.It \ef
+Write a <form-feed>.
+.It \en
+Write a <newline>.
+.It \er
+Write a <carriage-return>.
+.It \et
+Write a <tab>.
+.It \ev
+Write a <vertical-tab>.
+.It \e\e
+Write a <backslash> character.
+.It \e0 Ns Ar num
+Write an octet corresponding to the zero, one, two, or three digits octal number
+.Ar num .
+For example
+.Ql \e0
+writes the NULL byte, and
+.Ql \e01
+writes a octet of value 1.
+.El
.El
.Sh EXIT STATUS
.Ex -std
.Sh SEE ALSO
.Xr printf 1
.Sh STANDARDS
-Not XSI-compliant as
-.Fl n
-is parsed as an option and backslash operators aren't supported.
-Should be compliant with the rest of the
+Should be compliant with the
IEEE Std 1003.1-2024 (“POSIX.1”)
specification.
.Sh AUTHORS
diff --git a/cmd/echo.c b/cmd/echo.c
@@ -5,6 +5,7 @@
#define _POSIX_C_SOURCE 200809L
#include <stdbool.h>
#include <stdio.h> // perror
+#include <stdlib.h> // malloc
#include <string.h> // strlen
#include <unistd.h> // write
@@ -12,14 +13,37 @@ int
main(int argc, char *argv[])
{
size_t arg_len = 0;
- bool opt_n = false;
+ bool opt_n = false, opt_e = false;
argc--;
argv++;
- if(argc > 0 && strncmp(*argv, "-n", 3) == 0)
+ for(; argc > 0;)
{
- opt_n = true;
+ if(argv[0][0] != '-') break;
+
+ /* '--' needs to be passed as-is so no argc--,argv++ */
+ if(argv[0][1] == '-') break;
+
+ for(int i = 1; argv[0][i] != '\0'; i++)
+ {
+ switch(argv[0][i])
+ {
+ case 'n':
+ opt_n = true;
+ break;
+ case 'e':
+ opt_e = true;
+ break;
+ case 'E':
+ opt_e = false;
+ break;
+ default:
+ fprintf(stderr, "echo: warning: unknown option '-%c'\n", argv[0][i]);
+ break;
+ }
+ }
+
argc--;
argv++;
}
@@ -48,12 +72,94 @@ main(int argc, char *argv[])
if(opt_n) arg_len--; // no newline
- ssize_t nwrite = write(1, *argv, arg_len);
- if(nwrite < (ssize_t)arg_len)
+ char *d = *argv;
+ size_t d_len = arg_len;
+
+ char *newd = NULL;
+ if(opt_e)
+ {
+ newd = malloc(arg_len);
+ if(!newd)
+ {
+ fprintf(stderr, "echo: error: Failed to allocate for a copy of the strings\n");
+ return 1;
+ }
+
+ int di = 0;
+
+ for(size_t argi = 0; argi < arg_len; argi++)
+ {
+ if(d[argi] != '\\')
+ {
+ newd[di++] = d[argi];
+ continue;
+ }
+
+ switch(d[++argi])
+ {
+ case 'a':
+ newd[di++] = '\a';
+ break;
+ case 'b':
+ newd[di++] = '\b';
+ break;
+ case 'c':
+ newd[di++] = '\0';
+ goto p_break;
+ case 'f':
+ newd[di++] = '\f';
+ break;
+ case 'n':
+ newd[di++] = '\n';
+ break;
+ case 'r':
+ newd[di++] = '\r';
+ break;
+ case 't':
+ newd[di++] = '\t';
+ break;
+ case 'v':
+ newd[di++] = '\v';
+ break;
+ case '\\':
+ newd[di++] = '\\';
+ break;
+ case '0': /* \0 \0n \0nn \0nnn */
+ int nl = 1; // skip leading 0
+ int num = 0;
+ for(; nl < 4; nl++)
+ {
+ if(d[argi + nl] >= '0' && d[argi + nl] <= '7')
+ {
+ num = (num * 8) + (d[argi + nl] - '0');
+ }
+ else
+ break;
+ }
+ newd[di++] = num;
+ argi += (nl - 1);
+ break;
+ default:
+ newd[di++] = d[argi];
+ break;
+ }
+ }
+
+ newd[di] = '\0';
+ p_break:
+ d = newd;
+ d_len = di;
+ }
+
+ ssize_t nwrite = write(1, d, d_len);
+ if(nwrite < (ssize_t)d_len)
{
perror("echo: error: Failed writing");
+ if(opt_e) free(newd);
return 1;
}
+ if(opt_e) free(newd);
+
return 0;
}
diff --git a/test-cmd/echo.sh b/test-cmd/echo.sh
@@ -2,8 +2,9 @@
# SPDX-FileCopyrightText: 2017 Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>
# SPDX-License-Identifier: MPL-2.0
-target="$(dirname "$0")/../cmd/echo"
-plans=7
+WD="$(dirname "$0")/../"
+target="${WD}/cmd/echo"
+plans=17
. "$(dirname "$0")/tap.sh"
t 'empty' '' '
@@ -17,3 +18,39 @@ t -- '-n' '-n' ''
t -- '-n foo' '-n foo' 'foo'
t -- '-n foo bar' '-n foo bar' 'foo bar'
t -- '-n -- foo' '-n -- foo' '-- foo'
+
+wrap_od() {
+ "$target" "$@" | od -Ax -t x1 | tr '[:lower:]' '[:upper:]'
+}
+
+t_args 'e:newline' 'foo
+
+' -e 'foo\n'
+
+t_args 'en:newline' 'foo
+' -en 'foo\n'
+
+t_args 'e:simple_esc' "$(printf %b '\a\b\f\n\r\t\v')
+" -e '\a\b\f\n\r\t\v'
+
+t_args 'e:clear' 'foo' -e 'foo\cbar' 'baz'
+
+t_cmd 'e:0' '000000 66 6F 6F 00 62 61 72 00
+000008
+' wrap_od -en 'foo\0bar\0'
+
+# od -An -t o1 test-cmd/inputs/all_bytes | sed 's; ;\\0;g' | tr -d '\n'
+all_bytes_octal='\0000\0001\0002\0003\0004\0005\0006\0007\0010\0011\0012\0013\0014\0015\0016\0017\0020\0021\0022\0023\0024\0025\0026\0027\0030\0031\0032\0033\0034\0035\0036\0037\0040\0041\0042\0043\0044\0045\0046\0047\0050\0051\0052\0053\0054\0055\0056\0057\0060\0061\0062\0063\0064\0065\0066\0067\0070\0071\0072\0073\0074\0075\0076\0077\0100\0101\0102\0103\0104\0105\0106\0107\0110\0111\0112\0113\0114\0115\0116\0117\0120\0121\0122\0123\0124\0125\0126\0127\0130\0131\0132\0133\0134\0135\0136\0137\0140\0141\0142\0143\0144\0145\0146\0147\0150\0151\0152\0153\0154\0155\0156\0157\0160\0161\0162\0163\0164\0165\0166\0167\0170\0171\0172\0173\0174\0175\0176\0177\0200\0201\0202\0203\0204\0205\0206\0207\0210\0211\0212\0213\0214\0215\0216\0217\0220\0221\0222\0223\0224\0225\0226\0227\0230\0231\0232\0233\0234\0235\0236\0237\0240\0241\0242\0243\0244\0245\0246\0247\0250\0251\0252\0253\0254\0255\0256\0257\0260\0261\0262\0263\0264\0265\0266\0267\0270\0271\0272\0273\0274\0275\0276\0277\0300\0301\0302\0303\0304\0305\0306\0307\0310\0311\0312\0313\0314\0315\0316\0317\0320\0321\0322\0323\0324\0325\0326\0327\0330\0331\0332\0333\0334\0335\0336\0337\0340\0341\0342\0343\0344\0345\0346\0347\0350\0351\0352\0353\0354\0355\0356\0357\0360\0361\0362\0363\0364\0365\0366\0367\0370\0371\0372\0373\0374\0375\0376\0377'
+t_file 'en:all_bytes' "$WD"/test-cmd/inputs/all_bytes -en "$all_bytes_octal"
+
+t_args 'E:newline' 'foo\n
+' -E 'foo\n'
+
+t_args 'E:simple_esc' '\a\b\f\n\r\t\v
+' -E '\a\b\f\n\r\t\v'
+
+t_args 'E:clear' 'foo\cbar baz
+' -E 'foo\cbar' 'baz'
+
+t_args 'E:0' 'foo\0bar\0
+' -E 'foo\0bar\0'
