Commands by splante (8)

  • This is an alternative to #9131. ffmpeg didn't work on my .au files, though it did on the .wav ones. Also useful if you don't have ffmpeg but do have sox. Handily, sox already reports in seconds (decimal). Show Sample Output


    3
    get_duration() { durline=$(sox "$1" -n stat 2>&1|grep "Length (seconds):");echo ${durline#*\: }; }
    splante · 2011-09-02 15:22:43 1
  • Shorter, easier to remember version of cmd#7636 NTP is better, but there are situations where it can't be used. In those cases, you can do this to sync the local time to a server. Show Sample Output


    37
    date --set="$(ssh user@server date)"
    splante · 2011-08-30 20:03:06 4
  • This is an alternative to another command using two xargs. If it's a command you know there's only one of, you can just use: ls -l /proc/$(pgrep COMMAND)/cwd Show Sample Output


    3
    eval ls -l /proc/{$(pgrep -d, COMMAND)}/cwd
    splante · 2011-04-14 13:41:58 4
  • This is regarding the command 8263 using an alias to fill in command line options for psql. You can actually just type 'psql'. In order for that to work, you want to set environment variables PGDATABASE, PGHOST, PGUSER, and (except you're using the default) PGPORT. Also, you can add a line "host:port:dbname:user:password" (asterisk ok in some columns) to your ~/.pgpass file. Finally, if you don't like the aligned columns, you can add the line "\pset format unaligned" to your ~/.psqlrc file.


    2
    psql
    splante · 2011-04-08 18:35:20 0
  • Admittedly, I'd never have thought of this without the earlier examples, but here's one that you can execute from your workstation to just display the image from another, without separately doing a file transfer, etc. By the way, I hear a loud beep coming from the other room, so I guess it's not too stealthy :-D


    12
    ssh user@remote-host "DISPLAY=:0.0 import -window root -format png -"|display -format png -
    splante · 2011-04-08 01:07:41 1
  • The "type" builtin command is handy to find out what executable will be used if you issue a command. But on some distros, particularly when using /etc/alternatives, certain executables get buried under layers and layers of symbolic links and it becomes hard to find which one. If you put the above command in your .bashrc, it adds a "-c" option to the type command that will weed through the symbolic links and prints the actual file that will be executed. Show Sample Output


    0
    type () { if [ "$1" = "-c" ]; then shift; for f in "$@"; do ff=$(builtin type -p "$f"); readlink -f "$ff"; done; else builtin type $typeopts "$@"; fi; }
    splante · 2011-04-07 18:57:51 0
  • Credit goes to brun65i but he posted it as a comment instead as an alternative. I hadn't noticed the -h option on sort before and this seems like the cleanest alternative. Thanks Brun65i! Show Sample Output


    0
    du -h --max-depth=1 | sort -hr
    splante · 2011-04-07 18:01:18 0
  • ksh's version of cd has an optional syntax where you can type "cd old new" and it will replace "old" with "new" in your current directory and take you there. This is very handy when you have a parallel directory structure, like source and object directories. As suggested, you can just type cd ${PWD/old/new} to get this in bash, but this function in your .bashrc will let you type the ksh cd syntax and avoid typing the special characters while preserving other cd functionality. Show Sample Output


    0
    cd () { cdop=""; while [ "$1" != "${1#-}" ]; do cdop="${cdop} ${1}"; shift; done; if [ $# -eq 2 ]; then newdir="${PWD/$1/$2}"; [ -d "${newdir}" ] || { echo "no ${newdir}"; return 1; }; builtin cd $cdop "${newdir}"; else builtin cd $cdop "$@"; fi }
    splante · 2011-04-07 14:36:26 0

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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"

convert wav files to ogg
cd to the folder containing the wav files and convert them all to ogg format. in my sample output i use the -a and -l flags to set the author and album title. to get the oggenc program in ubuntu linux run: sudo apt-get install oggenc

Find files and calculate size of result in shell
Using find's internal stat to get the file size is about 50 times faster than using -exec stat.

easily strace all your apache *child* processes
Like the original version except it does not include the parent apache process or the grep process and adds "sudo" so it can be run by user.

Countdown Clock
The biggest advantage over atoponce's nifty original is not killing the scrollback. Written assuming bash, but shouldn't be terribly difficult to port to other shells. S should be multiple spaces, but I can't get commandlinefu to save/show them properly, any help?

TCP and UDP listening sockets
This command show listening sockets TCP and UDP. Useful for stop unwanted services from linux.

sniff network traffic on a given interface and displays the IP addresses of the machines communicating with the current host (one IP per line)

Commit only newly added files to subversion repository

Benchmark SQL Query
Benchmark a SQL query against MySQL Server. The example runs the query 10 times, and you get the average runtime in the output. To ensure that the query does not get cached, use `RESET QUERY CACHE;` on top in the query file.

Execute matlab sentences from command line
Execute matlab sentences in shell script: for var in `seq 0 0.2 1` ; do echo "my_function($var);" | matlab -nodisplay done


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