systemd-cat — Connect a pipeline or program's output with the journal
systemd-cat [OPTIONS...] [COMMAND] [ARGUMENTS...]
systemd-cat [OPTIONS...]
systemd-cat may be used to connect the standard input and output of a process to the journal, or as a filter tool in a shell pipeline to pass the output the previous pipeline element generates to the journal.
If no parameter is passed, systemd-cat will write everything it reads from standard input (stdin) to the journal.
If parameters are passed, they are executed as command line with standard output (stdout) and standard error output (stderr) connected to the journal, so that all it writes is stored in the journal.
The following options are understood:
-h, --help¶--version¶-t, --identifier=¶Specify a short string that is used to identify the logging tool. If not specified, no identification string is written to the journal.
-p, --priority=¶Specify the default
priority level for the logged
messages. Pass one of
"emerg",
"alert",
"crit",
"err",
"warning",
"notice",
"info",
"debug", or a
value between 0 and 7 (corresponding
to the same named levels). These
priority values are the same as
defined by
syslog(3). Defaults
to "info". Note that
this simply controls the default,
individual lines may be logged with
different levels if they are prefixed
accordingly. For details see
--level-prefix=
below.
--level-prefix=¶Controls whether lines
read are parsed for syslog priority
level prefixes. If enabled (the
default), a line prefixed with a
priority prefix such as
"<5>" is logged
at priority 5
("notice"), and
similar for the other priority
levels. Takes a boolean
argument.
Example 1. Invoke a program
This calls /bin/ls
with standard output and error connected to the
journal:
# systemd-cat ls
Example 2. Usage in a shell pipeline
This builds a shell pipeline also
invoking /bin/ls and
writes the output it generates to the
journal:
# ls | systemd-cat
Even though the two examples have very similar effects the first is preferable since only one process is running at a time, and both stdout and stderr are captured while in the second example, only stdout is captured.