oblog is a powerful, specialized echo tool. This is the exact same program than 66-yeller. This reimplementation avoids the dependency of the complete 66-tools set of tools.
oblog [ -h ] [ -d ] [ -s|S ] [ -1 file ] [ -2 file ] [ -z ] [ -n ] [ -c ] [ -p prog ] [ -v verbosity ] [ -i|w|W|t|T|f|F ] msg...
oblog writes the current system time, the name of the program, a colorized informative message (msg), depending on the options passed to one or two streams. By default, stream_1 points to stdout and stream_2 points to stderr. The \a, \b, \t, \n, \v, \f, and \r sequences are recognized in quoted strings, and are converted to the ASCII numbers 7, 8, 9, 10, 11, 12 and 13 respectively.
-h : prints this help.
-d : double-output. It writes on stream_1 and stream_2.
-s : switches streams. Stream_1 becomes stream_2 and stream_2 becomes stream_1.
-S : reads msg from stdin.
-1 file : redirects stream_1 to file. The file is opened for appending and created if it doesn't exist.
-2 file : redirects stream_2 to file. The file is opened for appending and created if it doesn't exist.
-z : enable color. If the stream_1 does not point to a terminal, the color is automatically disabled and the option has no effects.
-n : does not output a trailing newline.
-c : does not write the current sytem time. By default the current system time as an ISO timestamp. It can be set to a TAIN64(see Environment variable).
-p prog : use prog as the program name to display. By default oblog tries to find the name of the calling process by reading and parsing the /proc/<pid>/comm file. This option tells to oblog to use prog as the default program name to display.
-v verbosity : increases/decreases the verbosity of the command.
-i : does not write the informative message.
-w : prints a warning message.
-W : prints a warning message regardless the verbosity level. oblog follows the exact same verbosity rule as any other 66 tools. A verbosity set to 1 will not write a warning message. This option forces oblog to write a warning message even if the verbosity is less than 2.
-t : prints a tracing message.
-T : prints a tracing message regardless the verbosity level. oblog follows the exact same verbosity rule as any other 66 tools. A verbosity set to 2 will not write a tracing message. This option forces oblog to write a tracing message even if the verbosity is less than 3.
-f : prints a fatal message and dies with an 111 as exit code.
-F : prints a fatal message without dying.
A info(default) message will be:
<sytem time> <prog>: info: <msg>
where info is written in green color.
A warning message will be:
<sytem time> <prog>: warning: <msg>
where warning is written in yellow color.
A tracing message will be:
<sytem time> <prog>: tracing: <msg>
where tracing is written in white color.
A fatal message will be:
<sytem time> <prog>: fatal: <msg>
where fatal is written in red color.
The following environment variable can be set to configure the default oblog behavior. The corresponding options set at commandline overwrite the environment variable.
Corresponds to the -p option. Specifies the name of the program to display.
Corresponds to the -v option. Specifies the verbosity level to use.
Corresponds to the -z option. Tells to oblog to use color. A value of 1 enable the color, where 0 disable it.
Corresponds to the -d option. Tells to oblog to use double-output. A value of 1 switches on the double-output, where 0 switches off the double-output.
Corresponds to the -c option. Tells to oblog to output the current system time. A value of 1 outputs the system time where 0 does not.
Specifies the timestamp to use for the system time display. A value of 1 output the system time as ISO timestamp where 0 outputs the system time as TAIN64 timestamp.
Corresponds to the -1 option. Redirects the stream_1 to its value(e.g. REDIRFD_1=/dev/console). A value of 0 resets the stream_1 to its default value.
Corresponds to the -2 option. Redirects the stream_2 to its value(e.g. REDIRFD_2=/dev/null). A value of 0 resets the stream_2 to its default value.
Call oblog from a terminal where the shell is zsh:
% oblog this is an info message
2020-05-06 10:49:02.71 zsh: info: this is an info message
Same things but specifying the name of the program to print:
% oblog -p MyProg this is a warning message
2020-05-06 10:49:02.71 MyProg: info: this is a info message
This following message will not be displayed:
% oblog -p MyProg -w this following message will not be displayed
Where this one will be:
% oblog -p MyProg -W this following message will be displayed
2020-05-06 10:49:02.71 MyProg: warning: this following message will be displayed
Also, it can be:
% oblog -v2 -p MyProg -w this following message will be displayed
2020-05-06 10:49:02.71 MyProg: warning: this following message will be displayed
Do not display the system time:
% oblog -c -p MyProg what time is it\?
MyProg: info: what time is it?
Also do not display the informative message:
% oblog -ic -p MyProg what time is it\?
what time is it?
Colorize the output where what will be displayed in red color and time in yellow color:
% oblog -ic %r what %y time %n is it\?
what time is it?
Alos, it can be:
% oblog -ic %rwhat%y time%n is it\?
what time is it?
Append a trailing newline and a tabulation:
% oblog -ic what "time\nis\tit?"
what time
is it?
Use the double-output and redirects stream_2 to myfile file:
% oblog -d -2 myfile -p MyProg reads myfile to see again this message
2020-05-18 09:33:16.47 MyProg: info: reads myfile to see again this message
Reads msg from stdin:
% ls -la /tmp | oblog -p MyProg -S
2020-05-18 09:37:59.15 MyProg: info: total 840K
2020-05-18 09:37:59.15 MyProg: info: drwxrwxrwt 6 root root 220 May 18 09:07 ./
2020-05-18 09:37:59.15 MyProg: info: drwxr-xr-x 19 root root 4.0K May 16 09:13 ../
2020-05-18 09:37:59.15 MyProg: info: drwxr-xr-t 2 root root 40 May 18 06:57 .ICE-unix/
2020-05-18 09:37:59.15 MyProg: info: drwxrwxrwt 2 root root 60 May 18 06:57 .X11-unix/
Reads message from stdin. Does not display informative message and the system time. Uses double output and redirects stream_2 to myfile
% ls -la /tmp | oblog -cdi2 /tmp/myfile -S /tmp contents "->"
/tmp contents -> total 844K
/tmp contents -> drwxrwxrwt 6 root root 240 May 18 09:40 ./
/tmp contents -> drwxr-xr-x 19 root root 4.0K May 16 09:13 ../
/tmp contents -> drwxr-xr-t 2 root root 40 May 18 06:57 .ICE-unix/
/tmp contents -> drwxrwxrwt 2 root root 60 May 18 06:57 .X11-unix/
Use oblog in a sh script called script.sh with a pre-defined behavior set by the environment variables:
#!/bin/sh
export PROG=my_awesome_script
export VERBOSITY=2
export DOUBLE_OUTPUT=1
export REDIRFD_2=/tmp/my_awesome_script.log
set -e
if ! [ -e /etc/66/init.conf ]; then
oblog -f "file /etc/66/init.conf doesn't exist"
else
cat /etc/66/init.conf | oblog -Sic "%y->%n "
fi
if ! [ -e /etc/66/toto.conf ]; then
oblog -f "file /etc/66/toto.conf doesn't exist"
else
cat /etc/66/toto.conf | oblog -Sic "%y->%n "
fi
oblog you will never see this message
% ./script.sh
-> VERBOSITY=0
-> LIVE=/run/66
-> PATH=/usr/bin:/usr/sbin:/bin:/sbin:/usr/local/bin
-> TREE=boot
-> RCINIT=/etc/66/rc.init
-> RCSHUTDOWN=/etc/66/rc.shutdown
-> RCSHUTDOWNFINAL=/etc/66/rc.shutdown.final
-> UMASK=0022
-> RESCAN=0
-> ISHELL=/etc/66/ishell
2020-05-18 09:57:16.83 my_awesome_script: fatal: file /etc/66/toto.conf doesn't exist
% cat /tmp/my_awesome_script
cat /tmp/my_awesome_script.log
-> VERBOSITY=0
-> LIVE=/run/66
-> PATH=/usr/bin:/usr/sbin:/bin:/sbin:/usr/local/bin
-> TREE=boot
-> RCINIT=/etc/66/rc.init
-> RCSHUTDOWN=/etc/66/rc.shutdown
-> RCSHUTDOWNFINAL=/etc/66/rc.shutdown.final
-> UMASK=0022
-> RESCAN=0
-> ISHELL=/etc/66/ishell
2020-05-18 10:03:28.94 my_awesome_script: fatal: file /etc/66/toto.conf doesn't exist