the tee command does fine with file names, but not so much with file descriptors, such as &2 (stderr). This uses process redirection to tee to the specified descriptor. In the sample output, it's being used to tee to stderr, which is connected with the terminal, and to wc -l, which is also outputting to the terminal. The result is the output of bash --version followed by the linecount Show Sample Output
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. Show Sample Output
Output of a command as input to many Show Sample Output
only for sudo-style systems. Use this construct instead of I/O re-directors ``>'' or ``>>'' because sudo only elevates the commands and *not* the re-directors. ***warning: remember that the `tee` command will clobber file contents unless it is given the ``-a'' argument Also, for extra security, the "left" command is still run unprivileged. Show Sample Output
Sends both stdout and stderr to the pipe which captures the data in the file 'out.test' and sends to stdout of tee (likely /dev/tty unless redirected). Works on Bourne, Korn and Bash shells.
Streaming HTML5 compatible video (Ogg Theora video with Vorbis sound) to an Icecast server using dvgrab, ffmpeg2theora and oggfwd. In this example I'm merging stereo sound to mono (-c 1), saving the original dv for later higher quality on-demand video (tee dvstream.dv), saving the theora stream for immediate on-demand video, and publishing the stream in Xiph's stream directory (-p and the name and description). The URL of the video will be (depending on your server) http://my.icecastserver.com/stream.ogv which will play in newer Firefox, Chrome and Opera web browsers. Cortado (a Java player) can easily be used for IE. Note also that I'm using port 80, which is not the default port for Icecast, this is to avoid restrictive firewalls. Also note that ffmpeg2theora 0.25 and will heed the bitrates much better than former versions because of using libtheora 1.1 or newer.
Doesn't work so well if you connect from windows. Linux only sends LF where windows wants CRLF. The alternative command works better with windows, however it uses script and a named pipe.
when using named pipes only one reader is given the output by default. Also, most commands piped to by grep use a buffer which save output until tail -f finishes, which is not convenient. Here, using a combination of tee, sub-processes and the --line-buffered switch in grep we can workaround the problem.
The tee (as in "T" junction) command is very useful for redirecting output to two places. Show Sample Output
This is the solution to the common mistake made by sudo newbies, since
sudo echo "foo bar" >> /path/to/some/file
does NOT add to the file as root.
Alternatively,
sudo echo "foo bar" > /path/to/some/file
should be replaced by
echo "foo bar" | sudo tee /path/to/some/file
And you can add a >/dev/null in the end if you're not interested in the tee stdout :
echo "foo bar" | sudo tee -a /path/to/some/file >/dev/null
Show Sample Output
This will get the job done in the most efficient way -
spawning only one `rm` process.
"On-the-fly" find data is displayed through `tee` and
you should have plenty of time to ctrl-c if needed before it's too late.
You may need to re-run this after major Software Updates.
To leave more languages in, add more ``-and \! -iname "lang*"'' statements:
sudo find / -iname "*.lproj" -and \! -iname "en*" -and \! -iname "spanish*" -print0 | tee /dev/stderr | sudo xargs -0 rm -rfv
**Edit: note the 2nd sudo near the end of the pipeline - this is necessary.
We sometimes need to change kernel parameters by echoing the file . This needs root privilege and if we do it using sudo like this , it fails
sudo echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
-bash: /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor: Permission denied
We can achieve this with the tee command by just doing sudo without logging as root user
http://www.zaman4linux.in/2010/09/using-tee-to-echo-to-system-file-with.html
Summarize established connections after netstat output. Using tee and /dev/stderr you can send one command output to terminal before executing wc so you can summarize at the bottom of the output. Show Sample Output
In the above example 'muspi merol' (the output of the first rev command) is sent to stderr and 'lorem ipsum' (the output of the second rev command) is sent to stdout. rev reverse lines of a file or files. This use of tee allows testing if a program correctly handles its input without using files that hold the data. Show Sample Output
This is a cool trick to view the contents of the file on /dev/pts/0 (or whatever terminal you're using), and also send the contents of that file to another program by way of an unnamed pipe. All the while, you've not bothered saving any extra data to disk, like you might be tempted to do with sed or grep to filter output.
probably just like 1204, but uses tee as a filter (+ I actually understand how this one works)
Listen YouTube radios streaming. I use it on an alias to easily enter kinda flow state for study/programming. Show Sample Output
The simpler, 1-arg version is save_function(){ { date +"# %F.%T $1; declare -f "$1";}| tee -a ~/.bash_functions; }` Show Sample Output
If you as the sole user of a computer at home only don’t like needing to repeatedly type a password each time you run a command, using ‘NOPASSWD’ in sudoers for your specific username is for you.
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