1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
From: Georges Khaznadar <georgesk@debian.org>
Date: Sun, 27 Oct 2024 16:53:53 +0100
Subject: more_examples_for_crontab
This patch modifies crontab.5 in order to give useful
information about:
- using eval command, which makes easier to express
environment assignments inside commands to call with
cron.
- using leading zeroes instead of spaces to line up
columns
---
crontab.1 | 25 ++++++++++++++++++++++++-
crontab.5 | 31 ++++++++++++++++++++++++++++---
spcrc-crontab | 42 ++++++++++++++++++++++++++++++++++++++++++
spcrc-crontab-light | 44 ++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 138 insertions(+), 4 deletions(-)
create mode 100644 spcrc-crontab
create mode 100644 spcrc-crontab-light
diff --git a/crontab.1 b/crontab.1
index 2c87bc9..9da1e16 100644
--- a/crontab.1
+++ b/crontab.1
@@ -139,8 +139,31 @@ original behaviour by setting the environment variable
to 'N', which will cause the
.I crontab \-l
command to emit the extraneous header.
+.SH HIGHLIGHTING THE OUTPUT of crontab \-l
+The command
+.I crontab \-l
+outputs plain text. When a tty can support ANSI sequences to colourise
+this text, one can highlight the output, by calling:
+.I crontab \-l | spc -t crontab
+when the tty background is dark, or
+.I crontab \-l | spc -t crontab-light
+when this background is light.
+.PP
+The highlighting scheme can be modified by using customised versions of
+files
+.I /etc/supercat/spcrc-crontab*
+.PP
+One can also colourise this text with the program
+.I batcat
+provided by the package
+.I bat
+, here is an example:
+.nf
+.I crontab \-l | batcat --language Crontab
+.fi
+
.SH "SEE ALSO"
-crontab(5), cron(8)
+crontab(5), cron(8), spc(1)
.SH FILES
.nf
/etc/cron.allow
diff --git a/crontab.5 b/crontab.5
index 15f9fef..b3f3d15 100644
--- a/crontab.5
+++ b/crontab.5
@@ -64,8 +64,8 @@ tilde(~) expansion, thus lines like
.PP
.in +4n
.nf
-PATH = $HOME/bin:$PATH
-PATH = ~/bin:/usr/bin
+PATH=$HOME/bin:$PATH
+PATH=~/bin:/usr/bin
.fi
.in
.PP
@@ -80,7 +80,10 @@ C=$A $B
.in
.PP
There will not be any substitution for the defined variables in the
-last value.
+last value. However, with most shells you can also try e.g.,:
+.PP
+ P=PATH=/a/b/c:$PATH
+ 33 22 1 2 3 eval $P && some commands
.PP
Several environment variables are set up automatically by the
.IR cron (8)
@@ -290,6 +293,17 @@ Note that all the system-wide tasks will run, by default, from 6 am to 7 am. In
the case of systems that are not powered on during that period of time, only
the hourly tasks will be executed unless the defaults above are changed.
+.SH YET ANOTHER EXAMPLE
+
+In that example one can see that numbers can be prepended some 0, in order
+to line up columns.
+
+.nf
+17 * * * * root cd / && run-parts --report /etc/cron.hourly
+25 16 * * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )
+47 06 * * 7 root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.weekly )
+52 06 1 * * root test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.monthly )
+.fi
.SH SEE ALSO
cron(8), crontab(1)
@@ -367,6 +381,17 @@ the following wrapper code:
0 4 * * Sat [ "$(date +\e%e)" = "$(LANG=C ncal | sed \-n 's/^Sa .* \e([0\-9]\e+\e) *$/\e1/p')" ] && echo "Last Saturday" && program_to_run
.fi
+.SH USING EVAL TO WRAP MISC ENVIRONMENT SETTINGS
+The following tip is kindly provided by 積丹尼 Dan Jacobson:
+.PP
+ CONTENT_TYPE="text/plain; charset=UTF-8"
+ d=eval LANG=zh_TW.UTF-8 w3m -dump
+ 26 22 16 1-12 * $d https://www.ptt.cc/bbs/transgender/index.html
+.PP
+ it won't work without the eval. Saying
+ d=LANG=zh_TW.UTF-8 w3m -dump
+ will get
+ /bin/sh: LANG=zh_TW.UTF-8: command not found
.SH DIAGNOSTICS
cron requires that each entry in a crontab end in a newline character. If the
diff --git a/spcrc-crontab b/spcrc-crontab
new file mode 100644
index 0000000..8c0f147
--- /dev/null
+++ b/spcrc-crontab
@@ -0,0 +1,42 @@
+# ============ this file is to colorize crontabs ==========
+# 1 2 3 4 5
+#2345678901234567890123456789012345678901234567890123456789
+# HTML COLOR COL A N T STRING or REGULAR EXPRESSION
+#################### ### # # # ############################
+#Where:
+# HTML COLOR - Standard HTML Color name for HTML output
+# COL - Console color name from the list
+# red, yel, cya, grn, mag, blk, whi, blu
+# A - Attribute from the list
+# ' ' : normal
+# 'b' : bold
+# 'u' : underline
+# 'r' : reverse video
+# 'k' : blink
+# N - number of matches
+# ' ' : all
+# '0' : all
+# '1' - '9' : number of matches
+# T - type of matching to perform
+# 'c' : characters
+# 's' : string
+# 'r' : regex - case sensitive
+# 'R' : regex - case insensitive
+# 't' : regex with Unix time conversion
+# ' ' : default ('r' regex)
+# 1 2 3 4 5
+#2345678901234567890123456789012345678901234567890123456789
+# HTML COLOR COL A N T STRING or REGULAR EXPRESSION
+#################### ### # # # ############################
+# dom is blue + bold
+Blue blu b 5 \s+(\S+)
+# month is green + bold
+Green grn b 4 \s+(\S+)
+# dow is green + reverse video
+Green grn r 3 \s+(\S+)
+# hour is red + bold
+Red red b 2 \s+(\S+)
+# minute is red + reverse video
+Red red r 1 \s*(\S+)
+# comments are magenta
+Magenta mag (^#.*)
diff --git a/spcrc-crontab-light b/spcrc-crontab-light
new file mode 100644
index 0000000..81de807
--- /dev/null
+++ b/spcrc-crontab-light
@@ -0,0 +1,44 @@
+# ============ this file is to colorize crontabs ==========
+# 1 2 3 4 5
+#2345678901234567890123456789012345678901234567890123456789
+# HTML COLOR COL A N T STRING or REGULAR EXPRESSION
+#################### ### # # # ############################
+#Where:
+# HTML COLOR - Standard HTML Color name for HTML output
+# COL - Console color name from the list
+# red, yel, cya, grn, mag, blk, whi, blu
+# A - Attribute from the list
+# ' ' : normal
+# 'b' : bold
+# 'u' : underline
+# 'r' : reverse video
+# 'k' : blink
+# N - number of matches
+# ' ' : all
+# '0' : all
+# '1' - '9' : number of matches
+# T - type of matching to perform
+# 'c' : characters
+# 's' : string
+# 'r' : regex - case sensitive
+# 'R' : regex - case insensitive
+# 't' : regex with Unix time conversion
+# ' ' : default ('r' regex)
+# 1 2 3 4 5
+#2345678901234567890123456789012345678901234567890123456789
+# HTML COLOR COL A N T STRING or REGULAR EXPRESSION
+#################### ### # # # ############################
+# default is black
+Black blk (.*)
+# dom is blue + bold
+Blue blu b 5 \s+(\S+)
+# month is green + bold
+Green grn b 4 \s+(\S+)
+# dow is green + reverse video
+Green grn r 3 \s+(\S+)
+# hour is red + bold
+Red red b 2 \s+(\S+)
+# minute is red + reverse video
+Red red r 1 \s*(\S+)
+# comments are magenta
+Magenta mag (^#.*)
|
