Cheats

git

common commands

git log-short 10
git log -10
git log (commit)
git show (commit)
git show (commit):(path/file)
git merge (branch.to.merge.from)
git diff branch1 branch2 --name-only
git diff HEAD^^ HEAD 
git diff HEAD~1 HEAD 
git pull (remote-name)
git fetch (remote-name)
git checkout (branch-name)
git cherry-pick (commit)

aliases

alias gitlog="git log-short 30"
alias gcp="git cherry-pick"

squash

Compress multiple commits into one commit

Before
    (master)v1-->v2-->v3-->v4

After
    (master)v1-->v4

All changes in v2, v3 and v4 from Before are compressed into v4 in After.

To do this Squash operation:

1) git rebase -i (v1)
2) pick v2, squash (s) v3 and v4, save
3) comment out the comment to remove, save

git merge

Merge copies all feature branch changes to another branch.
(comment from 2024-11-30: I don't remember doing this at work at all.)

Before
    (master)v1-->v2 
                  \ 
                   \(br)-->b1-->b2

Git merge moves changes b1 and b2 from branch br to the master branch.

After
    (master)v1-->v2-->b1-->b2 
                  \
                   \(br)-->b1-->b2

git rebase

(comment from 2024-11-30: I don't remember doing this at work at all.)

Before
    (master)v1-->v2-->v3 
                  \ 
                   \(br)-->b1-->b2

After
    (master)v1-->v2-->v3 
                       \ 
                        \(br)-->b1-->b2

io

fd  = file descriptor
fd 0    = stdin
fd 1    = stdout
fd 2    = stderr

redirect stdout to file:                command > x
                same as:                command 1> x
redirect stderr to file:                command 2> x
redirect stdout to x, stderr to y:      command 1> x 2> y
redirect stderr and   stdout to x:      command &> x
                          same as:      command 2>&1 > x

find

find . -name "pattern"          # find any objects with a name pattern
find . -name "pattern" -type f  # find any files with a name pattern
find . -mtime -1                # find any objects modified within the past day
find . -name "regex_abc" -type f -exec grep -nH regex_xyz {} \;
        # find any file with regex_abc whose contents contain regex_xyz

journalctl

journalctl -u (name) -n (last-n-lines) -S (since) -U (until)

-u (name)          unit name
-f                 follow
-n                 show last 10 entries
-S --since (datetime)
-U --until (datetime)

Datetime options include:
"2022-01-01 09:00:00"
"2022-01-01"
09:00
today
yesterday
"1 hour ago"
"10 minutes ago"

vi

Finding things

f{c}         find the next instance of character 
F{c}         find the previous instance of character
/{pattern}   find the next instance of pattern
?{pattern}   find the previous instance of pattern
*            find the next instance of word under cursor
n            after find, go to the next instance
N            after find, go to the previous instance

Replacing things

:s/old/new/g     replace old with new only on current line
:n,m s/old/new/g replace old with new only on lines n to m
:%s/old/new/g    replace old with new globally
                 %s is special symbol in ed for all rows in file

Vital ops

u                undo last sequence of change

Buffers

:e               select a file to edit from local folder
:ls              list loaded files in buffers
:bn              buffer next
:bp              buffer previous
:bdelete n       buffer delete n

Windows

Ctrl-w s         split horizontal window
Ctrl-w v         split vertical window
Ctrl-w h/j/k/l   window jump- up, down, left, right
Ctrl-w Ctrl-w    window cycle
Ctrl-w c         close window
Ctrl-w =         resize window sizes all equal
Ctrl-w o         return to only One window

Visual blocks

v                select block by character
V                select block by line
Ctrl-v           select block

Moving around

$                jump to end of line
dw               delete word forward
daw              delete a word
dd               delete line

Reformatting

:set textwidth=65
v
gq

Bookmarks

m(c)             mark position with character c
'(c)             jump back to position c

Macros

q(r)             record a macro to register r
@(r)             playback macro r
n@(r)            playback macro r n number of times

Markdown

To turn off markdown marking _ as an error:
add these lines into:
/.vim/after/syntax/markdown.vim

syn match markdownError "\w\@<=\w\@="
syn match markdownIgnore "\$x_i\$"

ssh

ssh-keygen
ssh-add -l 
ssh-add (file containing private key)
ssh -T git@bitbucket.org

mounting

sudo fdisk -l 
sudo ntfsfix -d /dev/sdb1  // clear dirty flag

photos

mogrify -mattecolor white -frame 20x20 *jpg