sed edit file in place

Question

I am trying to find out if it is possible to edit a file in a single sed command without manually streaming the edited content into a new file and then renaming the new file to the original file name   I tried the -i option but my Solaris system said that -i is an illegal option   Is there a different way

User · Answer

If you are replacing the same amount of characters and after carefully reading “In-place” editing of files...

You can also use the redirection operator <> to open the file to read and write:

sed 's/foo/bar/g' file 1<> file

See it live:

$ cat file
hello
i am here                           # see "here"
$ sed 's/here/away/' file 1<> file  # Run the `sed` command
$ cat file
hello
i am away                           # this line is changed now

From Bash Reference Manual ? 3.6.10 Opening File Descriptors for Reading and Writing:

The redirection operator
[n]<>word
causes the file whose name is the expansion of word to be opened for both reading and writing on file descriptor n, or on file descriptor 0 if n is not specified. If the file does not exist, it is created.

User · Answer

You could use vi  vi -c   s foo bar g  my txt -c  wq

User · Answer

sed supports in-place editing  From man sed   -i SUFFIX   --in-place  SUFFIX       edit files in place  makes backup if extension supplied    Example   Let s say you have a file hello txtwith the text   hello world    If you want to keep a backup of the old file  use   sed -i bak  s hello bonjour  hello txt   You will end up with two files  hello txt with the content   bonjour world    and hello txt bak with the old content   If you don t want to keep a copy  just don t pass the extension parameter

User · Answer

Like Moneypenny said in Skyfall   Sometimes the old ways are best   Kincade said something similar later on     printf   s false true g nw n    ed  YourFileHere    Happy editing in place  Added   nw n  to write the file   Apologies for delay answering request

User · Answer

Versions of sed that support the -i option for editing a file in place write to a temporary file and then rename the file  Alternatively  you can just use ed   For example  to change all occurrences of foo to bar in the file file txt  you can do  echo   s foo bar g  w    tr      012    ed -s file txt  Syntax is similar to sed  but certainly not exactly the same  Even if you don t have a -i supporting sed  you can easily write a script to do the work for you   Instead of sed -i  s foo bar g  file  you could do inline file sed  s foo bar g    Such a script is trivial to write   For example     bin sh IN  1 shift trap  rm -f  quot  tmp quot   0 tmp    mktemp    lt  quot  IN quot   quot    quot   gt  quot  tmp quot   amp  amp  cat  quot  tmp quot   gt   quot  IN quot     preserve hard links  should be adequate for most uses

User · Answer

Very good examples  I had the challenge to edit in place many files and the -i option seems to be the only reasonable solution using it within the find command  Here the script to add  version   in front of the first line of each file   find   -name pkg json -print -exec sed -i   bak   1 s   version

User · Answer

You didn t specify what shell you are using  but with zsh you could use the      construct to achieve this  Something along the lines of   cp   sed     file  sync  file        is similar to  gt     but creates a temporary file which is automatically deleted when cp terminates

User · Answer

The following works fine on my mac  sed -i bak  s foo bar g  sample   We are replacing foo with bar in sample file  Backup of original file will be saved in sample bak  For editing inline without backup  use the following command  sed -i    s foo bar g  sample

User · Answer

The -i option streams the edited content into a new file and then renames it behind the scenes  anyway   Example   sed -i  s STRING TO REPLACE STRING TO REPLACE IT g  filename   and  sed -i     s STRING TO REPLACE STRING TO REPLACE IT g  filename   on macOS

User · Answer

On a system where sed does not have the ability to edit files in place  I think the better solution would be to use perl   perl -pi -e  s foo bar g  file txt   Although this does create a temporary file  it replaces the original because an empty in place suffix extension has been supplied

User · Answer

mv file txt file tmp  amp  amp  sed  s foo bar g   lt  file tmp  gt  file txt   Should preserve all hardlinks  since output is directed back to overwrite the contents of the original file  and avoids any need for a special version of sed

User · Answer

One thing to note  sed cannot write files on its own as the sole purpose of sed is to act as an editor on the  stream   ie pipelines of stdin  stdout  stderr  and other  gt  amp n buffers  sockets and the like   With this in mind you can use another command tee to write the output back to the file  Another option is to create a patch from piping the content into diff   Tee method  sed   regex    lt file gt    tee  lt file gt    Patch method  sed   regex    lt file gt    diff -p  lt file gt   dev stdin   patch   UPDATE   Also  note that patch will get the file to change from line 1 of the diff output   Patch does not need to know which file to access as this is found in the first line of the output from diff     echo foobar   tee fubar    sed  s oo u   fubar   diff -p fubar  dev stdin     fubar   2014-03-15 18 06 09 000000000 -0500 ---  dev stdin  2014-03-15 18 06 41 000000000 -0500                     1        foobar --- 1 ----   fubar    sed  s oo u   fubar   diff -p fubar  dev stdin   patch patching file fubar

User · Answer

Note that on OS X you might get strange errors like  invalid command code  or other strange errors when running this command   To fix this issue try   sed -i    -e  s STRING TO REPLACE STRING TO REPLACE IT g   lt file gt    This is because on the OSX version of sed  the -i option expects an extension argument so your command is actually parsed as the extension argument and the file path is interpreted as the command code   Source  https   stackoverflow com a 19457213

[unix] sed edit file in place

If you are replacing the same amount of characters and after carefully reading “In-place” editing of files...

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