Questions tagged [tee]
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.
235 questions
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Why does "seq 1000000 | tee /dev/stdout" produce more single-digit numbers than expected?
I'm in Linux and in Bash. I expect
seq 1000000 | tee /dev/stdout
to always output 9 numbers from 1 to 9 and their duplicates (18 in total). But when I do
seq 1000000 | tee /dev/stdout | grep -c '^[1-...
0
votes
0
answers
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Why does `<command> | tee /dev/tty | :` (where `:` is the "no effect" or "does nothing" bash builtin) display nothing? [duplicate]
I wanted to use tee /dev/tty to look into the stream passing through a pipeline. While making some tests, I observed the following:
~$ cd /proc/self/fd
/proc/self/fd$ ls
0 1 2 255
# Ok
/proc/self/...
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5
votes
2
answers
330
views
Duplicate stdout to pipe into another command with named pipe in POSIX shell script function
mkfifo foo
printf %s\\n bar | tee foo &
tr -s '[:lower:]' '[:upper:]' <foo
wait
rm foo
This is a working POSIX shell script of what I want to do:
printf %s\\n bar is symbolic for an external ...
- 3,554
2
votes
2
answers
507
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what is the meaning and usage of 2>&1 | tee /dev/stderr
for the following command
output=$(cat $file | docker exec -i CONTAINER COMMAND 2>&1 | tee /dev/stderr)
what is the meaning and usage of 2>&1 | tee /dev/stderr?
I google and 2>&...
- 133
1
vote
1
answer
243
views
bash: script running in pm2 unable to access file descriptors files at /dev/fd/
I have script script.sh:
#!/usr/bin/env bash
# pm2 seems to always run in `bash` regardless of `#!`
echo "running in $(readlink -f /proc/$$/exe)"
# Redirect to both stdout(1) and stderr(2)
...
- 313
0
votes
1
answer
101
views
How can I get stderr from mbuffer written to log file when using tee?
Having a bash script that essential only doing:
mbuffer --md5 -i dummy.tar -o /dev/null
A user of this script wants to use tee and store the output messages in a log file.
./script.sh 2>&1 | ...
- 3
0
votes
1
answer
157
views
can tee 'save' to stderr?
I know how to use tee, of course, I have used it many times. However, it is normally something like:
du -h /some/directory | sort -h | tee census
While this works fine, it means I don't see anything ...
- 779
0
votes
1
answer
213
views
Use grep to search stdout, without replacing stdout
At the moment, I have this in a wrapper script:
2>&1 ./update.sh | ts | tee -a ./update.log
and this in update.sh:
if apt full-upgrade -y | grep linux-headers
then
echo
echo Need to ...
- 153
8
votes
1
answer
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What is the '.tee_history' file?
This is a plaintext file, apparently limited to 300 lines. I use tee frequently on my system.
$ file .tee_history
.tee_history: Unicode text, UTF-8 text
$ wc -l .tee_history
300 .tee_history
$ tee --...
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2
votes
1
answer
163
views
How to "render" ouput from a command playing with tput so only the final terminal-postprocessed result is kept? [duplicate]
I captured the output of a script that uses tput to draw certain things on screen. When I perform cat myoutput then everything is well seen (looks like terminal reinterprets it from beginning), but ...
- 285
0
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1
answer
176
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Why is tee stopping in the middle when piped with nohup?
I'm running a script (in a Laravel project) that takes a few hours to complete. nohup to prevent it from exiting if my ssh session is disconnected.
nohup php artisan do:thing 2>&1 | tee ~/tmp
...
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1
answer
99
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What does the tee l2r or r2l argument mean?
I saw a socat example here, where they use
tee l2r | socat - "TCP:remote:5555" | tee r2l
what does the l2r or r2l mean?
- 131
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1
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Can I use tee to display output that other utilities tend to suppress?
The macos pbcopy utility grabs its input stream and stores it in the system clipboard, without displaying anything. So, when I want to copy/paste the output of a command in the terminal, I typically ...
- 115
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3
answers
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What is the `tee` command in Linux?
I am trying to interpret the following tee command:
cat colors.txt words.txt | tee colorsAndWords.txt | wc
Is my understanding, as follows, correct?
cat colors.txt words.txt: This command ...
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2
votes
2
answers
302
views
tee /dev/stderr inside script truncates output file if you redirect stderr
Given a script like below if I try to redirect stderr to a file, then the file is truncated at the point tee is used:
$ cat test.sh
#!/bin/bash
set -eux
echo before
echo '{ "foo": "...
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