How can I get "git show" to show diffs with full context?

Question

I am reviewing a very old commit. I want to see the changes a particular commit made but I want to see that in full context, i.e. I want to see whole file and the changes that person had made. The following command,

git show -w <commit-id>

is not showing me full context. Any suggestion?

Answer 1

git-show comes with the following flag

-U<n>, --unified=<n>
    Generate diffs with <n> lines of context instead of the usual
    three. Implies -p.

See the git-show man page for more details. By specifying a large enough <n>, e.g.

git show -U1000 <object>

you will get full context.

Example

Clone some repository for the sake of this example (e.g. the Git project's repo):

$ git clone https://github.com/git/git
$ cd git

Try running the command in question on some committed file (e.g. Documentation/RelNotes/2.3.0.txt):

$ git show -U100 -- Documentation/RelNotes/2.3.0.txt
commit 1e6f5b22ad318446500fbd3b94b733eddd5b6414
Author: Junio C Hamano <[email protected]>
Date:   Wed Jan 7 13:12:54 2015 -0800

    Fourth batch for 2.3 cycle

    Signed-off-by: Junio C Hamano <[email protected]>

diff --git a/Documentation/RelNotes/2.3.0.txt b/Documentation/RelNotes/2.3.0.txt
index 1b1dcbb..7f25bbf 100644
--- a/Documentation/RelNotes/2.3.0.txt
+++ b/Documentation/RelNotes/2.3.0.txt
@@ -1,165 +1,247 @@
 Git v2.3 Release Notes
 ======================

 Updates since v2.2
 ------------------

 Ports

  * Recent gcc toolchain on Cygwin started throwing compilation warning,
    which has been squelched.


 UI, Workflows & Features

  * It was cumbersome to use "GIT_SSH" mechanism when the user wanted
    to pass an extra set of arguments to the underlying ssh.  A new
    environment variable GIT_SSH_COMMAND can be used for this.

  * A request to store an empty note via "git notes" meant to remove
    note from the object but with --allow-empty we will store a
    (surprise!)  note that is empty.

  * "git interpret-trailers" learned to properly handle the
    "Conflicts:" block at the end.

  * "git am" learned "--message-id" option to copy the message ID of
    the incoming e-mail to the log message of resulting commit.

+ * "git clone --reference=<over there>" learned the "--dissociate"
+   option to go with it; it borrows objects from the reference object
+   store while cloning only to reduce network traffic and then
+   dissociates the resulting clone from the reference by performing
+   local copies of borrowed objects.
+
  * "git send-email" learned "--transfer-encoding" option to force a
    non-fault Content-Transfer-Encoding header (e.g. base64).
...

Sanity check

Compare the output of that command to the contents of Documentation/RelNotes/2.3.0.txt.

$ cat Documentation/RelNotes/2.3.0.txt
Git v2.3 Release Notes
======================

Updates since v2.2
------------------

Ports

 * Recent gcc toolchain on Cygwin started throwing compilation warning,
   which has been squelched.


UI, Workflows & Features

 * It was cumbersome to use "GIT_SSH" mechanism when the user wanted
   to pass an extra set of arguments to the underlying ssh.  A new
   environment variable GIT_SSH_COMMAND can be used for this.

 * A request to store an empty note via "git notes" meant to remove
   note from the object but with --allow-empty we will store a
   (surprise!)  note that is empty.

 * "git interpret-trailers" learned to properly handle the
   "Conflicts:" block at the end.

 * "git am" learned "--message-id" option to copy the message ID of
   the incoming e-mail to the log message of resulting commit.

 * "git clone --reference=<over there>" learned the "--dissociate"
   option to go with it; it borrows objects from the reference object
   store while cloning only to reduce network traffic and then
   dissociates the resulting clone from the reference by performing
   local copies of borrowed objects.

 * "git send-email" learned "--transfer-encoding" option to force a
   non-fault Content-Transfer-Encoding header (e.g. base64).

 * "git send-email" normally identifies itself via X-Mailer: header in
   the message it sends out.  A new command line flag --no-xmailer
   allows the user to squelch the header.

 * "git push" into a repository with a working tree normally refuses
   to modify the branch that is checked out.  The command learned to
   optionally do an equivalent of "git reset --hard" only when there
   is no change to the working tree and the index instead, which would
   be useful to "deploy" by pushing into a repository.

 * "git new-workdir" (in contrib/) can be used to populate an empty
   and existing directory now.