Disabling auto indent temporarily to pasteEdit

Sometimes you only need to paste some snippet of code, that already has indentation, so you can disable it only during the paste operation:

:set paste

then

:set nopaste

111. What could cause right click in putty session always insert Ctrl + c?

It is a putty problem, just install(maybe reinstall old version also work) the latest version, the problem is fixed.
I don't think it is because configuration, because after reinstall my other confguration is still there ( like font size, type), only the problem is resolved.

How to replace all %0,%1,%2,%3 to %{{[0-9]+}} in vim?

 (a)Select the text you want to replace.
 (b) :%s#%[0-4]#%{{[0-9]+}}#gc
 It is just one key.

 before:
 // CHECK-LABEL: xxsldwi_should_not_assert
// CHECK:  bitcast <2 x double> %0 to <4 x i32>
// CHECK-NEXT:  bitcast <2 x double> %1 to <4 x i32>
// CHECK-NEXT:  shufflevector <4 x i32> %2, <4 x i32> %3, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
// CHECK-NEXT:  bitcast <4 x i32> %4 to <2 x double>
after:
// CHECK-LABEL: xxsldwi_should_not_assert
// CHECK:  bitcast <2 x double> %{{[0-9]+}} to <4 x i32>
// CHECK-NEXT:  bitcast <2 x double> %{{[0-9]+}} to <4 x i32>
// CHECK-NEXT:  shufflevector <4 x i32> %{{[0-9]+}}, <4 x i32> %{{[0-9]+}}, <4 x i32> <i32 0, i32 1, i32 2, i32 3>
// CHECK-NEXT:  bitcast <4 x i32> %{{[0-9]+}} to <2 x double>

Break a previous commit into multiple commits? (How to split patches using git?)

git rebase -i will do it.

To split apart your most recent commit, first:

$ git reset HEAD~

Now commit the pieces individually in the usual way, producing as many commits as you need.

If it was farther back in the tree, then

$ git rebase -i HEAD~3

where 3 is how many commits back it is.

If it was farther back in the tree than you want to count, then

$ git rebase -i 123abcd^

where 123abcd is the SHA1 of the commit you want to split up.

When you get the rebase edit screen, find the commit you want to break apart. At the beginning of that line, replace pick with edit (e for short). Save the buffer and exit. Rebase will now stop just after the commit you want to edit. Then:

$ git reset HEAD~

Commit the pieces individually in the usual way, producing as many commits as you need, then

$ git rebase --continue

sed delete/insert/replace

101. How to delete lines using sed?
delete line 1-3
sed -i '1,3d' test.txt
delete line 2,5,8
sed -i '2d;5d;8d' testComparesllequ*.ll

Remove the line containing the string "awk," by using:
sed '/awk/d' filename.txt
sed -i '/; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py/d'

102. How to insert a line using sed?
sed -i  '1 i\
; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu testComparesiequ*.ll

103. sed replace a line:
sed 's/hello/bonjour/' greetings.txt
 Replacing in-place -i
sed ships with the -i flag. Let’s consult man sed:
sed -i 's/hello/bonjour/' greetings.txt

How to open vim and go to a specific line?

add +NUMBER after the vim file command, like:
 vim test/jtony.ll  +123
 This will open file  test/jtony.ll and goto line 123.

awk practice

$ cat /home/sfertile/bin/capture_dot
#!/bin/bash

grep Writing | awk -F\' '{print $2}'

This script grep the lines that contains "Writing" and then split the lines into different columns using the ' symbol seperator, and print the second element after splitting. 

It is equivalent to :

grep Writing | awk -F "'"  '{print $2}'

if we ignore, -F, the default separator will be space.

Revert changes in git

(1) How to revert files that are not staged in git?

For a specific file use:

git checkout path/to/file/to/revert

For all unstaged files use:

git checkout -- .

OR:

git checkout  .

(2) How to unstage a staged file?

git reset path/to/file/to/revert

(3) Is there a way to delete staged file completely?

 No, git reset will only unstage the staged files, it won't delete the changes,

if you want to delete it completely, you have to do git checkout in step one.

42. How to show where the current repo is pulled from?

git remote show origin
* remote origin
  Fetch URL: git@github.ibm.com:llvm/llvm-on-power.git
  Push  URL: git@github.ibm.com:llvm/llvm-on-power.git
  HEAD branch: master
  Remote branch:
    master tracked
  Local branch configured for 'git pull':
    master merges with remote master
  Local ref configured for 'git push':
    master pushes to master (up to date)

emcas replace-rectangle

Command    Key    Purpose
replace-rectangle    【Ctrl+x r t】    Replace text in a selected column.

try change this

 3c21 646f 6374
 6874 6d6c 3e3c
 2063 6861 7273
 202f 3e0a 3c6d
 6965 7770 6f72
 2277 6964 7468

to this

 3c21 cat 6374
 6874 cat 3e3c
 2063 cat 7273
 202f cat 3c6d
 6965 cat 6f72
 2277 cat 7468

    Put your cursor before “646f”.
    Call set-mark-command 【Ctrl+Space】.
    Move cursor to end of “6964”.
    Call replace-rectangle 【Ctrl+x r t】.

How to Split Windows in Emacs?

How to Split Windows in Emacs?

C-x 2

Split the selected window into two windows, one above the other (split-window-below).

 

C-x 3

Split the selected window into two windows, positioned side by side (split-window-right).



In order to exit splitting windows mode, you have to use:
C-x 0 
 to quit the current window
C-x 1
to quit all the extended window, i.e just leave one copy of the same view.

What is the difference between emacs and vim?

From Stackoverflow:
 http://stackoverflow.com/questions/1430164/differences-between-emacs-and-vim
"With Emacs you are expected to have it open 24/7 and live inside the program, almost everything you do can be done from there. You write your own extensions, use it for note taking, organisation, games, programming, shell access, file access, listening to music, web browsing. It takes weeks and weeks till you will be happy with it and then you will learn new stuff all the time. You will be annoyed when you don't have access to it and constantly change your config. You won't be able to use other peoples emacs versions easily and it won't just be installed. It uses Lisp, which is great. You can make it into anything you want it to be. (anything, at all)
With vim, it's almost always pre-installed. It's fast. You open up a file do a quick edit and then quit. You can work with the basic setup if you are on someone else's machine. It's not quite so editable; but it's still far better than most text editors. It recognises that most of the time you are reading/editing not typing and makes that portion faster. You don't suffer from emacs pinkie. It's not so infuriating. It's easier to learn."

In my opinion:
 Vim mode switch is annoying and also slow. Although emacs need to type more keys for most of the
editing task, but since you don't need to switch between different mode, so it is still faster when you are familiar with it. Also as mentioned here, it is more extendable and can used everywhere (gdb, shell) etc.

emacs Erasing Text

DEL

BACKSPACE

Delete the character before point, or the region if it is active (delete-backward-char).

Delete

Delete the character after point, or the region if it is active (delete-forward-char).

C-d

Delete the character after point (delete-char).

C-k

Kill to the end of the line (kill-line).

M-d

Kill forward to the end of the next word (kill-word).

M-DEL

Kill back to the beginning of the previous word (backward-kill-word).

How to copy and past a line in emcas?

down voteaccepted

C-a C-SPACE C-n M-w C-y which breaks down to C-a: move cursor to start of line C-SPACE: begin a selection ("set mark") C-n: move cursor to next line M-w: copy region C-y: paste ("yank")

git clean （ 清理）

git clean （ 清理）

有时，Git会提示“untracked working tree files”会“overwritten by checkout”。造成这种情况的原因有很多。不过通常来说，我们可以使用如下命令来保持工作树的整洁，从而防止这种情况的发生：

$ git clean -f     # remove untracked files
$ git clean -fd    # remove untracked files/directories
$ git clean -nfd   # list all files/directories that would be removed

emacs 按列块删除

“emacs 里面那个默认的列编辑不会出来像 vim 里面那样的矩形选区（不过有别的方法好像可以做到），所以当你选择的时候，还是按行来选择的，你只需要关心选择的起始点和结束点之间的那个矩形就好了，你的操作只会在里面起作用。” 之前我总是视图用vim 的方式理解emacs， 发现每次ctrl + x + r + k 都不能删除列方块，原来emacs 根本不会像vim 那样标记列矩阵块！而是从开始行的开始字符到终止行的终止字符直接所有的内容都被高亮选中，但是不用担心，删除的时候实际只会删除开始字符和终止字符直接的矩形块，别的会保留！ ~ 看来转换思维很重要。

kill-rectangle

try to delete the middle column
3c21 646f 6374
6874 6d6c 3e3c
2063 6861 7273
202f 3e0a 3c6d
6965 7770 6f72
2277 6964 7468

Command	Key	Purpose
kill-rectangle	【Ctrl+x r k】	Delete selected column of text.

1. Put your cursor before “646f”.
2. Call set-mark-command 【Ctrl+Space】.
3. Move cursor to end of “6964”. （move down 5 lines and right 3 columns).  At this time, the screen will looks like below (unlike vim, only the middle columns to be deleted are marked)

4. Call kill-rectangle. 

Ways to copy directory from one machine to another

There are several ways you can achieve this goal. Two the common ways are using rsync and scp.

(1)  rsync

rsync -a dir1/ dir2

This will archive and copy directory dir1 recursively to dir2.

The -a option is a combination flag.

It stands for "archive" and syncs recursively and preserves symbolic links, special and device files, modification times, group, owner, and permissions.

 If you want to copy to another machine as destination. Just add the machine full name as the prefix for 

dir2. 

syntax:

rsync -a dir1/    user_name@neodynium.bell.ca:dir2

 e.g:

rsync -a test1/  jyj407@tj12.zte.com.cn:test2

 The above  command copies test1 directory recursively from the current machine to the remote 

tj12.zte.com.cn machine directory test2.  Here, ':' colon symbol stands for the home directory for user

jyj407.

(2) Another way is use scp.

scp -r dir1/    user_name@neodynium.bell.ca:dir2

 The scp command is similar to rsync, but slower than rsync, especially for large directory with 

tons of files. Also rsync does incremental  copy, scp will copy everything. So generally speaking,

I would recommend  using 'rsync' instead of 'scp'.

gdb basics tutorial

      Note these commands are universal except the first two are specific for llvm build and debug. For other application you want to debug, simply build a debug version using your own way (either make or cmake), then just 'gdb yourApplication' . For some complex applications you may need --args to pass some flags.

(1)    Build a debug version executable.  

cmake -DGCC_INSTALL_PREFIX=/home/llvm/gcc/install/gcc-6.2.0 -DCMAKE_BUILD_TYPE="Debug" -DBUILD_SHARED_LIBS=ON -DLLVM_ENABLE_ASSERTIONS=ON  ~/src/llvm ; make -j20

(2)    Start gdb:

gdb --args /home/jtony/debug/bin/llc  test/CodeGen/PowerPC/expand-isel.ll

(3)    Query function:

  info func expandMergeableISELs  (info func MergeableISEL also works, fuzzy matching?)

(4)     Set break points:

Function breakpoint:

b[reak] function_name

e.g: b(reak) PPCExpandISEL::expandMergeableISELs

set breakpoint at a specified file-line pair:

b[reak] file.cpp:7

break current line:

b[reak]

conditional break is also allowed:  b[reak] file.cpp:7 if a > 5

(5)    Start the program and run to breakpoint

r[un]

Run to next breakpoint:

c[ontinue]

typing r(un) again would restart the program from beginning

(6)    Switch to TUI mode

lay src          (ctrl + x  + a)

(7)    Debug

Step into:   ‘s[tep]’             -- will go into a function call, and walk through every line of code

Step over:  ‘n[ext]’            -- treat function call as one instruction, won’t go into it

Step out:    ‘fin[ish]’          --  finish the rest of the function call and return to the caller

Note: press ENTER gdb will repeat the same command you just gave to it

(8)    Save/restore/show breakpoints

Save breakpoints:  save breakpoints filename

Reload breakpints:  source filename

Show breakpoints:   ‘info break’

(9)    Show commands history: 

‘show commands’

(10) Print/ptype

Print value of a variable:      p[rint] varName

Print in hexadecimal:       p[rint]/x  varName

print the type of var:             ptype ‘varName’

(11) Calling stack

Print calling stack:   ‘where’ or ‘backtrace’

Navigate between calling stack:

Go up one level:       ‘up’

Go down one level:  ‘down’

Go up N level:           ‘up  N’

Go down N level;     ‘down N’

refresh the screen:   ‘refresh’

(12) Call function

call a function: call function_name(parameters)

(13) jump to a line (not safe, unpredictable, unless you know what you are doing)   

                 First set a break point on the line you want to jump to:   b[reak]   line_number    e.g  b 321

                 Then jump line number:  jump  line_number                       e.g  jump 321

New skills learned during the tutorial:

n(ext) N       will step over N steps, if N = 1, is equivalent to just n(ext)

git clean

40. How to remove all the untrack files in the current branch?

    Step 1 is to show what will be deleted by using the -n option:
    git clean -n
    Clean Step - beware: this will delete files:
    git clean -f



Ref:     http://stackoverflow.com/questions/61212/how-to-remove-local-untracked-files-from-the-current-git-branch

git revert

 How to revert one commit (may not be the HEAD one) ?
git revert commit_number
git revert 6d80fe73c689b51358b05cc945a53c44a092ebe3

What is GNU Libtool?

Introduction to GNU Libtool

GNU libtool is a generic library support script. Libtool hides the complexity of using shared libraries behind a consistent, portable interface.

To use libtool, add the new generic library building commands to your Makefile, Makefile.in, or Makefile.am. See the documentation for details. 

Ref:
https://www.gnu.org/software/libtool/libtool.html

VIM: Deleting from current position until a character

Switch to command mode in vim and then try d + t + space. In general d + t + x deletes from current position till just before x. Just t + x moves the cursor to just before character x in current line.

To delete up to and including the space, use d + f + space  (or d + t + space)

Reference: http://stackoverflow.com/questions/1607904/vim-deleting-from-current-position-until-a-space

Emacs editing by column

For example here is the text I want to edit:

foo
foo
foo

And here is the text result I want to have:

bar foo
bar foo
bar foo

Use rectangles (as mentioned in another answer). 

The explicit directions for that are:

1. goto first line, first column
2. Ctrl-Space
3. goto last line (first column)
4. Ctrl-x r t bar space RET