Commands by lijeb (0)

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Perform Real-time Process Monitoring Using Watch Utility

Given $PID, print all child processes on stdout
Simpler.

Check if a package is installed. If it is, the version number will be shown.
If the first two letters are "ii", then the package is installed. You can also use wildcards. For example, . $ dpkg -l openoffice* . Note that dpkg will usually not report packages which are available but uninstalled. If you want to see both which versions are installed and which versions are available, use this command instead: . $ apt-cache policy python

put command in a loop to keep trying a connection
This will keep trying to reconnect your netcat connection can be used with SSH or Telnet, just substitute nc for ssh or telnet very useful for troubleshooting VPNs were you want to send continuous packets towards a destination to trace.

Print every Nth line (to a maximum)
Thanks to knoppix5 for the idea :-) Print selected lines from a file or the output of a command. Usage: $ every NTH MAX [FILE] Print every NTH line (from the first MAX lines) of FILE. If FILE is omitted, stdin is used. The command simply passes the input to a sed script: $ sed -n -e "${2}q" -e "0~${1}p" ${3:-/dev/stdin} print no output $ sed -n quit after this many lines (controlled by the second parameter) $ -e "${2}q" print every NTH line (controlled by the first parameter) $ -e "0~${1}p" take input from $3 (if it exists) otherwise use /dev/stdin ${3:-/dev/stdin}

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Colored status of running services
Replace service --status-all 2>&1 by service --status-all 2>/dev/null to hide all services with the status [ ? ]

quickly formats a fat partition. usefull for flash drives

copy timestamps of files from one location to another - useful when file contents are already synced but timestamps are wrong.
Sometimes when copying files from one place to another, the timestamps get lost. Maybe you forgot to add a flag to preserve timestamps in your copy command. You're sure the files are exactly the same in both locations, but the timestamps of the files in the new home are wrong and you need them to match the source. Using this command, you will get a shell script (/tmp/retime.sh) than you can move to the new location and just execute - it will change the timestamps on all the files and directories to their previous values. Make sure you're in the right directory when you launch it, otherwise all the touch commands will create new zero-length files with those names. Since find's output includes "." it will also change the timestamp of the current directory. Ideally rsync would be the way to handle this - since it only sends changes by default, there would be relatively little network traffic resulting. But rsync has to read the entire file contents on both sides to be sure no bytes have changed, potentially causing a huge amount of local disk I/O on each side. This could be a problem if your files are large. My approach avoids all the comparison I/O. I've seen comments that rsync with the "--size-only" and "--times" options should do this also, but it didn't seem to do what I wanted in my test. With my approach you can review/edit the output commands before running them, so you can tell exactly what will happen. The "tee" command both displays the output on the screen for your review, AND saves it to the file /tmp/retime.sh. Credit: got this idea from Stone's answer at http://serverfault.com/questions/344731/rsync-copying-over-timestamps-only?rq=1, and combined it into one line.

PDF simplex to duplex merge
Joins two pdf documents coming from a simplex document feed scanner. Needs pdftk >1.44 w/ shuffle.


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