Bash – Merge two command results to one line when redirecting stdout

bashstdout

In a cron script I want to log CPU temperatures in the format

[datetime] temp

using date and acpi -t. How can I redirect (>>) these two commands to a single line in the log file?

Best Answer

Try simply doing:

echo $(date) $(acpi -t) >> your_log_file

You might want to specify a compact date format to make your log file more easy to parse and to be independent of environment/locale settings (something like $(date +"%Y%m%d %H%M%S") for example).

Related Solutions

Bash – Two commands, one pipeline

You can pass multiple names to dig:

dig +nottlid -t any bix.hu www.bix.hu | egrep -v "^;;|^;|^$" | sort

Redirecting/grep’ing an existing shell’s STDOUT

There is a clever hack mentioned here that uses GDB to attach to the process, and a utility named dupx wraps up this functionality.

From the dupx manpage:

Dupx is a simple utility to remap files of an already running program. Shells like Bash allow easy input/output/error redirection at the time the program is started using >, < - like syntax, e.g.: echo 'redirect this text' > /tmp/stdout will redirect output of echo to /tmp/stdout.

Standard shells however do not provide the capability of remapping (redirecting) of output (or input, or error) for an already started process. Dupx tries to address this problem by using dup(2) system call from inside gdb(1). Dupx is currently implemented as a simple shell wrapper around a gdb script.

Best Answer

Related Solutions

Bash – Two commands, one pipeline

Redirecting/grep’ing an existing shell’s STDOUT

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