How to append output to the end of a text file

Question

How do I append the output of a command to the end of a text file

User · Answer

To append a file use   gt  gt   echo  hello world    gt  gt  read txt    cat read txt      echo  hello siva   gt  gt  read txt    cat read txt   then the output should be  hello world     from 1st echo command hello world     from 2nd echo command hello siva   To overwrite a file use   gt   echo  hello tom   gt  read txt cat read txt     then the out put is     hello tom

User · Answer

For example your file contains      1   mangesh 001    cat output txt     1     2     EOF   if u want to append at end of file then ---- remember spaces between  text      filename       2  mangesh 001    echo somthing to append  gt  gt  output txt cat output txt      1     2     EOF     somthing to append   And to overwrite contents of file      3   mangesh 001    echo  somthing new to write   gt  output tx cat output tx     somthing new to write

User · Answer

I would use printf instead of echo because it s more reliable and processes formatting such as new line  n properly   This example produces an output similar to echo in previous examples   printf  hello world    gt  gt  read txt    cat read txt hello world   However if you were to replace printf with echo in this example  echo would treat  n as a string  thus ignoring the intent  printf  hello nworld    gt  gt  read txt    cat read txt hello world

User · Answer

You can use the    operator  This will append data from a command to the end of a text file   To test this try running   echo  Hi this is a test   gt  gt  textfile txt   Do this a couple of times and then run   cat textfile txt   You ll see your text has been appended several times to the textfile txt file

User · Answer

I often confuse the two  Better to remember through their output   gt  for Overwrite   touch someFile txt   echo  quot  gt  quot   gt  someFile txt   cat someFile txt    gt    echo  quot  gt  quot   gt  someFile txt   cat someFile txt    gt    gt  gt  for Append   echo  quot  gt  quot   gt  someFile txt   cat someFile txt    gt    echo  quot  gt  quot   gt  gt  someFile txt   cat someFile txt    gt  gt

User · Answer

I d suggest you do two things    Use  gt  gt  in your shell script to append contents to particular file  The filename can be fixed or using some pattern  Setup a hourly cronjob to trigger the shell script

User · Answer

for the whole question   cmd  gt  gt  o txt  amp  amp       wc -l  lt o txt  -eq 720     amp  amp  mv o txt   date   F  o txt   this will append 720 lines  30 24  into o txt and after will rename the file based on the current date   Run the above with the cron every hour  or  while   do     cmd  gt  gt  o txt  amp  amp       wc -l  lt o txt  -eq 720     amp  amp  mv o txt   date   F  o txt     sleep 3600 done

User · Answer

Using tee with option -a  --append  allows you to append to multiple files at once and also to use sudo  very useful when appending to protected files   Besides that  it is interesting if you need to use other shells besides bash  as not all shells support the   and    operators  echo  hello world    sudo tee -a output txt   This thread has good answers about tee

User · Answer

Use  gt  gt  instead of  gt  when directing output to a file   your command  gt  gt  file to append to   If file to append to does not exist  it will be created   Example     echo  hello   gt  file   echo  world   gt  gt  file   cat file  hello world

User · Answer

Use the  gt  gt  operator to append text to a file

User · Answer

Use command  gt  gt  file to append to to append to a file    For example echo  Hello   gt  gt  testFile txt  CAUTION  if you only use a single  gt  you will overwrite the contents of the file  To ensure that doesn t ever happen  you can add set -o noclobber to your  bashrc    This ensures that if you accidentally type command  gt  file to append to to an existing file  it will alert you that the file exists already  Sample error message  file exists  testFile txt  Thus  when you use  gt  it will only allow you to create a new file  not overwrite an existing file

[bash] How to append output to the end of a text file

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