Install a package in centos

# tar -xvf findutils-4.7.0.tar
# cd findutils-4.7.0
# ./configure
#make
#make install
# xargs --version
xargs (GNU findutils) 4.7.0
Copyright (C) 2019 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Eric B. Decker, James Youngman, and Kevin Dalley.
# 

VIM - Tips

MAPPING

# mapping ESC key to F5

:imap <f5> <esc>

SEARCH

# search white space 15 or more

/\s\{15,}

# searches for trailing white space and deletes it everywhere in the buffer

:%s/\s\+$//e

:%s/\s\+$ or :%s/\s\+$//

The "e" flag tells ":substitute" that not finding a match is not an error.

# selected ares, search _eng, add # in the beginning of the line

:'<,'>g/\%V_eng/s/^/#/

# Visual Select

:'<,'>s/\%V1/0/g

selected area, replace 1 to 0

# replace selected lines

:'<,'>s/eqr/pattern":"fsfpb0ph","

:'<,'>s/\%V-/ /g

#replace "-" with " " in selected area

#replace space with new line

:%s/ /\r/g

# To change to the directory of the currently open file for all windows

:cd %:p:h

# To change to the directory only for the current window

:lcd %:p:h

     % gives the name of the current file,

     %:p gives its full path,

     %:p:h gives its directory (the "head" of the full path).

# replace " " with a new line

:%s/ /\r/g

# combine multiple lins to one line

%j

# Find each occurrence of 'foo' (in all lines), and replace it with 'bar'.

:%s/foo/bar/g

# Find each occurrence of 'foo' (in the current line only), and replace it with 'bar'.

:s/foo/bar/g

# search [00:49:33.151] with any number

/[..:..:..\....\]

zz - move current line to the middle of the screen

zt - move current line to the top of the screen

zb - move current line to the bottom of the screen

z<enter> - move current line to the bottom of the screen

# Show all tabs:

/\t

# Show spaces before a tab:

/ \+\ze\t

# Convert tabs to space

:retab

# Show trailing whitespace:

/\s\+$

# Show trailing whitespace only after some text (ignores blank lines):

/\S\zs\s\+$

# ignore case

:set ignorecase

:set ic

# consider case

se noic

# search a pattern and add a character at the beginning of the line

:%g/_eng/substitute/^/#/

Recording macro

Each register is identified by a letter a to z.

# To enter a macro, type:

q<letter><commands>q

# To execute the macro

 <number> times (once by default), type:

<number>@<letter>

# So, the complete process looks like:

qd  start recording to register d

... your complex series of commands

q   stop recording

@d  execute your macro

@@  execute your macro again

# end of recording macro #

# to join all lines in a file into a single line

# "ggVG" visually selects all lines, and "J" joins them.

ggVGJ

# Align Colmun

:%!column -t #Align Colmun

# search square bracket of "A" char

/\["A", *[0-9-e.]*\]                                                                                                                                          2230,461      44%

# search square bracket of "A" char and replace

:%s/\["A", *[0-9-e.]*\]/["A", "auto"]/

# align column for selected column

:'<,'>%!column -t

# select columbn and override it

???

# split window horizontal

:sp filename

# split window vertical

:vs filename

# grep file names and open it

gvim `grep tmLatchTrim patterns/* -l`

# Switching case of characters

Toggle case "HellO" to "hELLo" with g~ then a movement.

Uppercase "HellO" to "HELLO" with gU then a movement.

Lowercase "HellO" to "hello" with gu then a movement.

Python: control statement

scope=[1,2,3]
for x in scope
   print(x)
   break
else:
   print("Perfect")

Output:
1

break를 지우면,
Output:
1
2
3
Perfect


while condition:
   repeating_code
   continue   # return to while condition
   ...
   break       # exit while condition

Python: tips for variables

키워드를 변수로 사용 : SyntaxError
키워드 확인
>>> import keyword
>>> keyword.kwlist

module 이름을 변수로 사용: 모듈사용못함, 하면 TypeError
>>> abs=1 # now abs type is 'int'
# How to use abs() function?

>>> abs = 1
>>> type(abs)
<type 'int'>         # abs is int variable
>>> abs(-2)        # TypeError

Traceback (most recent call last):
  File "<pyshell#137>", line 1, in <module>
    abs(-2)
TypeError: 'int' object is not callable
>>> del abs       # delete int variable; remain internal function abs()
>>> type(abs)
<type 'builtin_function_or_method'>
>>> abs(-2)
2
>>>

Python: calling a class/method with parenthesis vs. no-parenthesis? whats the diff?

calling a class/method with parenthesis vs. no-parenthesis? whats the diff?

>>> class Service:

secret = "He is a alian."

def setname(self, name):

self.name=name

def sum(self,a,b):

print "{}, {}+{} = {}".format(self.name,a,b,a+b)

code source: https://wikidocs.net/28

aman = Service()

awoman = Service

>>> type(aman)

<type 'instance'>

>>> type(awoman)

<type 'classobj'>

>>> 

classobj can assign a instance.

>>> kim=awoman()

>>> type(kim)

<type 'instance'>

>>> aman.setname("Strong")

>>> awoman.setname("Beauty")

Traceback (most recent call last):

  File "<pyshell#58>", line 1, in <module>

    awoman.setname("Beauty")

TypeError: unbound method setname() must be called with Service instance as first argument (got str instance instead)

>>>