tee is a command line utility that reads the standard input and writes to the standard output as well as a file specified as an argument. Use this tag for questions about the tee command.

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5
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1answer
332 views

Using 'ping', 'cut' and 'tee' together

So, I understand that by using 'tee' I can redirect the output of a command such as 'ping' to stdout as well as a file. For example: > ping google.com | tee somefile This would display the ping ...
5
votes
2answers
45 views

Understanding i/o redirection in the context of _process substitution_

Running GNU bash, version 4.3.11(1)-release (x86_64-pc-linux-gnu). I don't really understand process substitution (ProcSub) from the perspective of a user interested in lifting the hood on i/o ...
2
votes
1answer
25 views

Appending to a file suffix range with echo and tee

I am unable to figure out how to properly pipe and tee to append to a range of files. Instead of manually typing them out echo "help!" | tee >> file1 file2 file3 I am trying to figure out: ...
1
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0answers
18 views

How to capture “$?” before tee smashes it? [duplicate]

I've got a test script that repeatedly builds a library under different configurations. It also tee's the output for postmortem failures: $MAKE" static dynamic cryptest.exe 2>&1 | tee -a ...
2
votes
1answer
51 views

How do I let tee print all file descriptors to screen but only save stdout to file?

Suppose my program prints to multiple file descriptors and I need to watch all of the outputs as they are being printed but only save stdout to a file. How do I do that?
0
votes
3answers
105 views

ping output statistics to file

[root@localhost ~]# while true; do timeout -s 2 1h ping 96.120.16.121 | ts '%Y-%m-%d %H:%M:%S |' | tee -a ping.log; done easier to read format: #!/bin/bash while true; do timeout -s 2 1h ...
-3
votes
2answers
56 views

Can not pipe the `pwd` result to tee [closed]

I use Ubuntu 14.04. When i execute ls | tee - it works fine. But pwd | tee - just output absolute path only once and does not exit! i need to Ctrl+C to stop it. Any clue? EDIT: I use bash.
0
votes
4answers
47 views

How to log from inside the script along with stdout

I am aware that I can log using tee But I want to log from inside my script, at the same time display the content on the stdout. Example, my code looks something like this: names=$(print("name1 ...
0
votes
0answers
31 views

Preserve colours when piping to tee

I have made a little program where I update homebrew with brew update, then I send the output to a log file, but I also want to keep it on the terminal so I use tee. The problem is, it doesn't show ...
1
vote
3answers
133 views

How can I un-write protect file made by tee?

I have a small program and I want to ensure that it works on both write protected files and un-write protected files. So, instead of using echo $text > $file or echo $text >> $file, I am ...
2
votes
4answers
237 views

Extract two values from the output of a command

I'm using the following command in a script to get synthetic wifi info: echo "$( iw dev wlp1s0 link | grep '^\s*SSID:\s' | sed -r 's/^\s*SSID:\s//' ) $( iw dev wlp1s0 link | grep ...
7
votes
1answer
228 views

Does tee slow down pipelines?

I am wondering whether tee slows down pipelines. Writing data to disk is slower than piping it along, after all. Does tee wait with sending data through to the next pipe until it has been written to ...
0
votes
1answer
520 views

How to redirect output of a 'xterm -hold -e' command

I know you can use tee to log output from a command in a terminal, e.g.: df -h | tee ~/log.txt However, how can I do this with a more complex command like this: xterm -hold -e program arg1 arg2 ...
1
vote
2answers
783 views

Redirect script output to /dev/tty1 and also capture output to file

I want to display text output on the console that is always displayed on a small screen on my Raspberry Pi. The following code works for showing that text output: cd ...
21
votes
4answers
1k views

Is it possible to redirect the output of a command into more than one command?

As far as I know, I can use the tee command to split the standard output onto the screen and further files: command -option1 -option2 argument | tee file1 file2 file3 Is it possible to redirect ...
1
vote
1answer
299 views

Redirect all bash script output (from inside the script) to two files: one append, one rewrite; but discard output to the console

I can easily redirect both standard and error output of a bash script to the file, while discarding an output to console with simple exec statement: exec &>>/var/log/backup.log But how do ...
2
votes
6answers
321 views

using tee to output intermediate results to stdout instead of files

I know that to capture a pipeline's contents at an intermediate stage of processing, we use tee as ls /bin /usr/bin | sort | uniq | tee abc.txt | grep out , but what if i don't want to redirect the ...
3
votes
2answers
262 views

How to use tee to capture STDOUT from a code block to a filename defined within the block?

I want to send STDOUT for a script block to a file which name is defined by a variable within the block. However, when I use tee, it seems the variable outside the block doesn't exist anymore. Without ...
1
vote
1answer
84 views

Output Redirection

I am using the tee command to output the compilation errors of a program into a file along with the terminal. gcc hello.c | tee file.txt This is the command I have used. The compilation errors are ...
0
votes
1answer
46 views

Why doesn't this tee with process substitution produce the 1st and chosen lines? [duplicate]

What I want is printing the output the first line ( table head ) of ps aux and the grep result. After search, I come up with following. ps aux | tee >(head -1 > /dev/tty) | grep mongo But I ...
0
votes
1answer
340 views

Using tee or pipe to log console output will cause my program not to start [duplicate]

I'm running hostapd on my raspberry PI to let it function as an accesspoint. It's working fine with the following command: sudo hostapd /etc/hostapd/hostapd.conf This will start hostapd and log all ...
0
votes
1answer
122 views

Keep PHP's output with tee -a

Normally when running PHP script in web server mode, this would show up: $ php -S 0.0.0.0:12345 PHP 5.6.1 Development Server started at Mon Nov 24 14:09:22 2014 Listening on http://0.0.0.0:12345 ...
0
votes
3answers
151 views

How to save in a variable the convert from decimal to binary without use an echo

I've been trying to save in a variable the value of the convert of a number from decimal to binary, like this: num1=10 echo "obase=2;$num1" | bc | tee -a register.txt but I don't want to show it ...
1
vote
1answer
196 views

Redirect output to stdout and pipe to a binary

I have a nice PS1 line in my .bash_profile, and I want to copy it to another machine. So I want to view it AND copy it to my clipboard. I can't figure out how to string the commands to do this ...
1
vote
2answers
463 views

Append a file, output to screen and redirect from stderr all at once, without tee

I'm running a time dd command in a shell script, and I'd like to output the results to a file, and print it out on the screen. The line that I'm currently running is: (time dd of=$dest_filepath ...
2
votes
2answers
125 views

How to write to a file with netcat? And set it to grow to a certain size and begin overwriting itself?

I'm currently writing a program that prints to a Zebra printer. Because my office doesn't have a zebra printer, we print to a linux VM running netcat with nc -k -l -p 9100 | tee labels.txt so that we ...
1
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0answers
112 views

Verbose output in logfile and simple output on screen?

Let's say I have the following script: script.sh and i want the verbose output in a logfile and simple output on screen. Logfile should contain the csh -v script.sh output, and on the screen should ...
1
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0answers
16 views

Test execution output of a command before a pipe [duplicate]

I would like to test the execution of a php script that redirect its stdout and stderr to a file with tee. php /path/to/script --param 2>&1 | tee -a /path/to/log if ( test $? -ne 0 ); then ...
3
votes
2answers
8k views

Using exec and tee to redirect logs to stdout and a log file in the same time [duplicate]

In a bash script, how can I redirect all standard outputs to a log file and tee the output on the screen using exec ? log_file="$HOME/logs/install.txt-`date +'%Y-%m-%d_%H-%M-%S'`" [ -f "$log_file" ] ...
8
votes
2answers
561 views

Redirecting output depending on grep regex

I am using gradle run to start a REST server. The output of the REST server looks like this: XXX.XXX.XX.XXX - <moreinfo> randomtext randomtext XXX.XXX.XX.XXX - <moreinfo> XXX.XXX.XX.XXX - ...
2
votes
1answer
557 views

bottomless tee?

I was just playing around in the terminal and I did this: printf 'some string\n' | { tee /dev/fd/3 | { : && sed 's/some/string/' } } 3>&0 I was really surprised when ...
2
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2answers
574 views

Process substitution with tee and paste

I'm trying to pipe a command through the output of two other commands and then merge the results of the two process substitutions. An example that gets me close is: command | tee >(sed -rn ...
1
vote
2answers
264 views

grep a keyword from Mplayer output and send the rest to file

I am using mplayer. I want to send everything to a log file (/tmp/server.log), but I want the Volume output to be written to the terminal. I have seen that there is a way to split the output with tee, ...
4
votes
2answers
165 views

Running several times the same command with several aguments after a pipe

I have a key (of random binary data) that gets generated by get_key. And with this key, I can do several things with my encrypted files. For example, I can decrypt them. get_key | tee >(decrypt ...
1
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0answers
34 views

Filter partial output of some script [duplicate]

I need to analyze the output of some script So, I know their header and their tail of some part of the output script, but not the content. I found an approach [1] But I need something like: $ ...
14
votes
3answers
2k views

tee stdout to stderr?

I'd like to send stdout from one process to the stdin of another process, but also to the console. Sending stdout to stdout+stderr, for instance. For example, I've got git edit aliased to the ...
3
votes
2answers
207 views

tee / sudo password cache conflict?

I have a large bash script (Ubuntu 12.04). The script is designed to be invoked by a regular user; only certain commands within the script run with sudo. It is not an option to run the entire script ...
3
votes
4answers
249 views

saving output of another command

I need to select certain lines from the log file and also save them to a text file. I tried the following but none of them are working as expected. The file "todel.txt" shows 0 bytes. tail -f ...
4
votes
1answer
545 views

Logging interactive input and output without capturing all typed input and control characters

I am trying to log output from an interactive command-line program; units, specifically. I have tried using tee like this: units | tee units.log or script like this: script -c units units.log ...
4
votes
3answers
4k views

How to get mplayer to play from stdin?

Why doesn't this work? cat /dev/video1 | mplayer - If I could get that to work, then I could play & record video at the same time using 'tee' to feed mplayer and mencoder. I want to play live ...
0
votes
2answers
114 views

Why does this command work for logging script output?

This command does not store the output of my script in the log file: . myscript.sh | tee -a log_file.log However this next command does store the output in the log file. . myscript.sh 2>&1 ...
5
votes
2answers
547 views

Reusing pipe data for different commands

I would like to use the same pipe for different applications, like in: cat my_file | { cmd1 cmd2 cmd3 } Cmd1 should consume part of the input. Cmd2 should consume another part and so on. ...
2
votes
2answers
2k views

Use sudo tee with heredoc to append to existing file

From Generate script in bash and save it to location requiring sudo we have this method, which I like: sudo tee "$OUTFILE" > /dev/null <<'EOF' foo bar EOF However, I would like to use that ...
4
votes
1answer
1k views

How can I use tee and logger -t “some tag:”?

I've seen in another post which shows how to use tee and logger as shown below. tee >(logger) <<< "System Load is OK : $Current_loadadv" >(logger) is bash syntax to create a file ...
3
votes
2answers
397 views

How to duplicate a stream and process both parts in a streaming way?

Sometimes I want to insert something in a pipeline for reporting or some other secondary use. It might be as simple as wc -l, or a more complex beast like awk or even a python script. It'd be nice to ...
0
votes
1answer
999 views

Why doesn't this variable assignment work when using tee?

Consider: $ FILE_NAME=`(cat somefile | head -1)` | tee -a dump.txt $ echo $FILE_NAME $ Now, why doesn't the output of (cat somefile | head -1) reach the standard input of tee ..? If the output ...
8
votes
3answers
8k views

Output to stdout and at the same time grep into a file

I have a script that outputs text to stdout. I want to see all this output in my terminal, and at the same time I want to filter some lines and save them in a file. Example: $ myscript Line A Line B ...
10
votes
3answers
4k views

tee + cat: use an output several times and then concatenate results

If I call some command, for instance an echo I can use the results from that command in several other commands with tee. Example: echo "Hello world!" | tee >(command1) >(command2) ...
2
votes
1answer
636 views

How to `tee` dropping all CR lines only in the file but not stdout?

When using e.g. rsync, I'd like to tee its output such that I can both view the current progress live, and have a log for later. Using just piping | tee logfile the logfile will contain many lines à ...
1
vote
2answers
870 views

Print/Tee to console without passing output to pipe

Is there a way to print or tee one thing to the console and still pass something else through to the next pipe? Something like: echo dog | printOrWhatnot "PUTTING MY THING DOWN" | sed 's/dog/cat/g' | ...