Commands tagged stdout (10)


  • 59
    strace -ff -e trace=write -e write=1,2 -p SOME_PID
    oernii2 · 2010-04-20 08:55:54 14
  • similar to the previous command, but with more friendly output (tested on linux)


    10
    strace -ff -e write=1,2 -s 1024 -p PID 2>&1 | grep "^ |" | cut -c11-60 | sed -e 's/ //g' | xxd -r -p
    systemj · 2010-04-23 16:22:17 5
  • You have a script where =ALL= STDERR should be redirected to STDIN and you don't want to add "2>&1" at the end of each command... E.G.: ls -al /foo/bar 2>&1 Than just add this piece of code at the beginning of your script! I hope this can help someone. :)


    9
    exec 2>&1
    morgents · 2010-08-05 08:24:18 7
  • Useful to recover a output(stdout and stderr) "disown"ed or "nohup"ep process of other instance of ssh. With the others options the stdout / stderr is intercepted, but only the first n chars. This way we can recover ALL text of stdout or stderr Show Sample Output


    3
    strace -e write=1,2 -p $PID 2>&1 | sed -un "/^ |/p" | sed -ue "s/^.\{9\}\(.\{50\}\).\+/\1/g" -e 's/ //g' | xxd -r -p
    glaudiston · 2010-10-06 19:37:39 5
  • I've had a horrible time trying to pipe the output of some shell built-ins like 'time' to other programs. The built-in doesn't output to stdout or stderr most of the time but using the above will let you pipe the output to something else. Show Sample Output


    1
    TIME=$( { time YOUR_COMMAND_HERE; } 2>&1 ) ; echo $TIME
    allrightname · 2010-11-18 15:48:05 10
  • save as shell script and pipe your command output Show Sample Output


    0
    #!/bin/zsh SHL='\\e[0;31m' EHL='\\e[0m' while read line; do TEXT=$line for SSTR in $*; do TEXT=$(echo $TEXT | sed -e "s:$SSTR:${SHL}${SSTR}${EHL}:g") done echo -e $TEXT done
    steigr · 2012-06-06 12:57:50 4
  • This will be very helpful when you are debugging shell scripts, where you don?t want to display the echo statement and interested in only looking at the error messages. Similarly use 2> to supress error messages Show Sample Output


    0
    cat file.txt > /dev/null
    ankush108 · 2012-06-26 18:34:12 4
  • Very convenient to for sending data to the clipboard for processing. However, note that tee will affect the buffering of the output (stdout won't be update very live). Show Sample Output


    0
    alias t="tee >(pbcopy)"
    lgarron · 2014-01-24 12:41:07 10
  • Run a job in the background and prefix it's output with some string. This is particularly useful if you are running inside a docker container in a startup script (sue me, I'll run two jobs in a docker container if I want to) and you can run something like: /usr/sbin/nginx 2>&1 | awk '{print "[NGINX] " $0}' & /opt/jws-3.1/tomcat8/bin/catalina.sh run 2>&1 | awk '{print "[TOMCAT] " $0}' & while true; do ; done it can also be combined with tee to create a file log as well as a stdout log, for example if the script above where a script called "/bin/start-container.sh" then you could run /bin/start-container.sh | tee /var/log/containerlogs Show Sample Output


    0
    nginx 2>&1 | awk '{print "[NGINX] " $0}' &
    hvindin · 2017-04-25 22:18:38 20
  • Adds the stdout (standard output) to the beginning of logfile.txt. Change "command" to whatever command you like, such as 'ls' or 'date', etc. It does this by adding the output to a temporary file, then adding the previous contents of logfile.txt to the temp file, then copying the new contents back to the logfile.txt and removing the temp file.


    -2
    command > tmp && cat logfile.txt >> tmp && tmp > logfile.txt && rm tmp
    akoumjian · 2009-04-05 22:00:32 12

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Run a program transparently, but print a stack trace if it fails
For automated unit tests I wanted my program to run normally, but if it crashed, to add a stack trace to the output log. I came up with this command so I wouldn't have to mess around with core files. The one downside is that it does smoosh your program's stderr and stdout together.

Format date/time string for a different day
The "date' command has options to easily format the date, day, month, time, etc. But what if you want a relative date or time. Like, I wanted yesterday's date in a particular format. You may want the exact date of "2 months ago" or "-3 days" nicely formatted. For that, you can use this command. The --date option takes fuzzy parameters like the ones mentioned in the previous sentence.

List all open ports and their owning executables
Particularly useful on OS X where netstat doesn't have -p option.

Change string in many files at once and more.
Find all files that contain string XXX in them, change the string from XXX to YYY, make a backup copy of the file and save a list of files changed in /tmp/fileschanged.

Calculate days on which Friday the 13th occurs
Alter the years in the first brace expansion to select your year range. Modify date format to your liking but leave " %w" at the end.

Filter IP's in apache access logs based on use
Show's per IP of how many requests they did to the Apache webserver

Insert an element into xml
This inserts an element as last child under /breakfast_menu/food in simple.xml. xml used - http://www.w3schools.com/xml/simple.xml

Squish repeated delimiters into one
This can be particularly useful used in conjunction with a following cut command like $echo "hello::::there" | tr -s ':' | cut -d':' -f2 which prints 'there'. Much easier that guessing at -f values for cut. I know 'tr -s' is used in lots of commands here already but I just figured out the -s flag and thought it deserved to be highlighted :)

HDD Performance Write Test
Test your XFS filesystem and Raptor hard drives for write performance.

Output as many input
Output of a command as input to many


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