Execute a command with a timeout

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Execute a command with a timeout

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 timelimit -t100 somecommand

I found this in Ubuntu repos, and consider it better than timeout.

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by David Winterbottom (codeinthehole.com)

URL: http://feedproxy.google.com/~r/Command-line-fu/~3/h72xZsssE4o/execute-a-command-with-a-timeout

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write the output of a command to /var/log/user.log… each line will contain $USER, making this easy to grep for.

write the output of a command to /var/log/user.log… each line will contain $USER, making this easy to grep for.

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 log() { (echo "$ [email protected]";[email protected]) | logger -t $USER; }

This command is useful if you want to copy the output of a series of commands to a file, for example if you want to pastebin the output from ‘uname -a’, ‘lspci -vvv’ and ‘lsmod’ for video driver trouble-shooting on your favorite Linux forum.

‘log’ takes all the following arguments as a command to execute, with STDOUT sent to /var/log/user.log. The command is echoed to the log before it is executed.

The advantages of using logger (as opposed to appending output from commands to a file) are 1) commands are always appended to the logs… you don’t have to worry about clobbering your log file accidentally by using ‘>’ rather than ‘>>’ 2) logs are automatically cleaned up by logrotate.

The following functions allow you to mark the start and end of a section of /var/log/user.log.

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startlog() { export LOGMARK=$(date +%Y.%m.%d_%H:%M:%S); echo "$LOGMARK.START" | logger -t $USER; }

then

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endlog() { "$LOGMARK.END" | logger -t $USER; }

printlog will print all lines between $LOGMARK.START and $LOGMARK.END, removing everything that is prepended to each line by logger.

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printlog() { sudo sed -n -e "/$LOGMARK.START/,/$LOGMARK.END/p" /var/log/user.log| sed "s/.* $USER: //"; }

Caveats: I’m sure that those could use some cleanup and error checking… there are unchecked dependencies between printlog and endlog, as well as between endlog and startlog.

It might be useful for ‘log’ to also send stderr to logger as well.

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by David Winterbottom (codeinthehole.com)

URL: http://feedproxy.google.com/~r/Command-line-fu/~3/6DP_QDTn2IM/write-the-output-of-a-command-to-varloguser.log…-each-line-will-contain-user-making-this-easy-to-grep-for.

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Empty a file

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This one is for those who know the “touch” command. Hope all of us do not follow a  command just because it is on one of the popular site without trying to understand the command and the output.

Empty a file

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touch file

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URL: http://feedproxy.google.com/~r/Command-line-fu/~3/zwubbQvws5g/empty-a-file

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