linux

reference
The Bash Shell Startup Files
Advanced Bash-Scripting Guide
download pdf from here or here
Perform tab-completion for aliases in Bash
dot_file: .bash_aliases
killbutmakeitlooklikeanaccident.sh

prompts

reference:
* imarslo: color
* Bash/Prompt customization
* Bash/Prompt customization
Colors using tput
What color codes can I use in my PS1 prompt?
joseluisq/terminal-git-branch-name.md
How to show git branch in terminal and change terminal colours
8 Useful and Interesting Bash Prompts
* 2.5. Bash Prompt Escape Sequences
* My Ultimate PowerShell prompt with Oh My Posh and the Windows Terminal

settings

[!NOTE|label:inputrc]
* iMarlso: inputrc
* marslo/mylinux/inputrc

# https://marslo.github.io/ibook/screenshot/colors/ansi/color-formatting.png
fgc=$(RGBcolor 5 6 8)                             # 240;  fgc=$(RGBcolor 5 6 5)  # 237
COL_SD_GREEN='\[\033[32;2m\]'                     # COL_SD_GREEN='\[\033[2;32m\]'
COL_IF_SL_RED='\[\033[0\;31m\]'
COL_DEFAULT="\[\033[38;5;${fgc}m\]"               # "\[$(tput setaf ${fgc})\]"; $"\e[38;5;${fgc}m";
COL_IF_DEFAULT="\[\033[38\;5\;${fgc}m\]"          # COL_IF_DEFAULT="\[\033[1\;38\;5\;${fgc}m\]"  | COL_IF_DEFAULT="${COL_IF_SD_GREEN}"
COL_RESET='\[\033[1m\]'                           # COL_RESET="\[$(tput sgr0)\]" | COL_RESET='\[\033[1m\]'
COL_NONE='\[\033[0m\]'                            # COL_NONE='\[\033[38;5;3m\]'

PS1="\\n${COL_RESET}${COL_DEFAULT}╭╶ (\\u@\\h${COL_RESET} "
PS1+="${COL_SL_RED}\\w${COL_RESET}${COL_DEFAULT}) "
PS1+="\$(__git_ps1 \"- (${COL_SD_GREEN}%s${COL_NONE}${COL_DEFAULT}) \")${COL_RESET}"
PS1+="${COL_DEFAULT}\`if [ \$? = 0 ]; then echo ${COL_IF_DEFAULT}\⏵; else echo ${COL_IF_SL_RED}\⏵; fi\`${COL_RESET}"
PS1+="\\n${COL_DEFAULT} \$ ${COL_RESET}"
PS1+="${COL_NONE}"
PS2="${COL_DEFAULT}  -> ${COL_RESET}${COL_NONE}"
PS4=' ${BASH_SOURCE}:$FUNCNAME:$LINENO: '

PS1="\\n${COL_RESET}${COL_DEFAULT}╭╶ (\\u@\\h${COL_RESET} "
PS1+="${COL_SL_RED}\\w${COL_RESET}${COL_DEFAULT}) "
PS1+="\`__git_ps1 '- (%s) '\`"
PS1+="${COL_RESET}${COL_DEFAULT}->${COL_RESET}"
PS1+="\\n${COL_DEFAULT}╰╶ ${COL_RESET}"
PS1+="\`if [ \$? = 0 ]; then echo ${COL_IF_DEFAULT}\\$; else echo ${COL_IF_SL_RED}\\$; fi\` ${COL_RESET}"
PS1+="${COL_NONE}"
# PS2="${COL_DEFAULT} |-> ${COL_RESET}${COL_NONE}"
PS2="${COL_DEFAULT}  -> ${COL_RESET}${COL_NONE}"
PS4=' ${BASH_SOURCE}:$FUNCNAME:$LINENO: '

export PS1 PS2 PS4

UMARK='\[\033(0\]l\[\033(B\]'
DMARK='\[\033(0\]m\[\033(B\]'
LMARK='\[\033(0\]q\[\033(B\]'

COL_SL_GREEN='\[\033[32;0m\]'
COL_SD_GREEN='\[\033[32;2m\]'                     # COL_SD_GREEN='\[\033[2;32m\]'
COL_SD_YELLOW='\[\033[2;33m\]'
COL_SL_YELLOW='\[\033[0;33m\]'
COL_B_YELLOW='\[\033[2;33m\]'
COL_IF_SD_YELLOW='\[\033[2\;33m\]'

COL_D_BLACK='\[\033[30;1m\]'
COL_L_BLACK='\[\033[30;0m\]'
COL_SD_BLACK='\[\033[1;30m\]'
COL_SL_BLACK='\[\033[0;30m\]'
COL_SD_RED='\[\033[1;31m\]'
COL_SL_RED='\[\033[0;31m\]'
COL_SD_BLUE='\[\033[1;34m\]'
COL_SL_BLUE='\[\033[0;34m\]'
COL_L_RED='\[\033[31;0m\]'
COL_D_RED='\[\033[31;1m\]'

COL_IF_D_BLACK='\[\033[30\;1m\]'
COL_IF_L_BLACK='\[\033[30\;0m\]'
COL_IF_SD_BLACK='\[\033[1\;30m\]'
COL_IF_SL_BLACK='\[\033[0\;30m\]'
COL_IF_SL_YELLOW='\[\033[0\;33m\]'
COL_IF_D_RED='\[\033[31\;1m\]'
COL_IF_SD_RED='\[\033[1\;31m\]'
COL_IF_SL_RED='\[\033[0\;31m\]'
COL_IF_SL_GREEN='\[\033[0\;32m\]'
COL_IF_SD_GREEN='\[\033[2\;32m\]'
COL_IF_SL_BLUE='\[\033[0\;34m\]'
COL_IF_SD_BLUE='\[\033[1\;34m\]'

if [ -z "$DISPLAY" ]; then
  export PS1="\n${COL_D_BLACK}┌─ (\u@\h ${COL_RESET} ${COL_D_RED}\w${COL_RESET}${COL_D_BLACK}) ->${COL_RESET}\n${COL_D_BLACK}└─ ${COL_RESET}\`if [ \$? = 0 ]; then echo ${COL_SD_BLACK}\\$ ${COL_RESET}; else echo ${COL_SD_RED}\\$ ${COL_RESET}; fi\`${COL_NONE}"
  export PS2="${COL_D_BLACK} -> ${COL_RESET}${COL_NONE}"
else
  export PS1="\n${COL_D_BLACK}${UMARK}${LMARK} (\u@\h ${COL_RESET} ${COL_D_RED}\w${COL_RESET}${COL_D_BLACK}) ->${COL_RESET}\n${COL_D_BLACK}${DMARK}${LMARK} ${COL_RESET}\`if [ \$? = 0 ]; then echo ${COL_SD_BLACK}\\$ ${COL_RESET}; else echo ${COL_SD_RED}\\$ ${COL_RESET}; fi\`${COL_NONE}"
  export PS2="${COL_D_BLACK} ->${LMARK} ${COL_RESET}${COL_NONE}"
fi

# for mac os -> Solarized Dark
export PS1="\n${COL_DEFAULT}┌─ (\u@\h${COL_RESET} ${COL_SD_RED}\w${COL_RESET}${COL_DEFAULT}) ->${COL_RESET}\n${COL_DEFAULT}└─ ${COL_RESET}\`if [ \$? = 0 ]; then echo ${COL_IF_DEFAULT}\\$ ${COL_RESET}; else echo ${COL_IF_SL_RED}\\$ ${COL_RESET}; fi\`${COL_NONE}"

PS4

[!NOTE|label:references:]
Setting $PS4 using bash -c
Why does Bash reset PS4 value to its default value when starting a script?

show timestamp

$ bash -xc $'PS4=\'+ $(date "+%T %x ($LINENO) : ")\'; echo ABC; echo XYZ'
+ PS4='+ $(date "+%T %x ($LINENO) : ")'
+ 15:45:51 08/29/2024 (1) : echo ABC
ABC
+ 15:45:51 08/29/2024 (1) : echo XYZ
XYZ

# or
$ PS4='+ \D{%s} ($LINENO) ' bash -xc 'echo ABC; echo XYZ'
+ 1724971586 (1) echo ABC
ABC
+ 1724971586 (1) echo XYZ
XYZ

# or
$ cmd=$(cat <<'EOF'
PS4='+ $(date "+%T %x ($LINENO) : ")'
echo ABC
echo XYZ
EOF
)

bash -xc "$cmd"

show process id

$ env -i SHELLOPTS=xtrace PS4='$(id)' ./test

colors

Bash tips: Colors and formatting (ANSI/VT100 Control sequences)

# https://misc.flogisoft.com/bash/tip_colors_and_formatting
#  ----+---+---+----+---+----       --------+--------     ----+------+------
# | ⌌・| ⠋ | ⌜ | ╭╶ | ┌ | ┌─ |    | 0\;xxm | Normal |    | \e | \033 | \x1B |
# | ⌎・| ⠦ | ⌞ | ╰╶ | └ | └─ |    | 1\;xxm | Bright |     ----+------+------
#  ----+---+---+----+---+----      --------+--------
#
#  ---+--------------++---------------------++----------------------+    +-----------------
# | # |  color name  ||      foregrand      ||      background      |    |   attribute     |
#  ---+--------------++---------------------++----------------------+    +---+-------------
# | 9 | Default      ||      \e[0;39m       ||       e[0;49m        |    | 0 | Normal      |
# | 0 | Black        || \e[0;30m |          || \e[0;40m |           |    | 1 | Bold        |
# | 1 | Red          || \e[0;31m |          || \e[0;41m |           |    | 2 | Faint       |
# | 2 | Green        || \e[0;32m |          || \e[0;42m |           |    | 3 | Italic      |
# | 3 | Yellow       || \e[0;33m |          || \e[0;43m |           |    | 4 | Underline   |
# | 4 | Blue         || \e[0;34m |          || \e[0;44m |           |    | 5 | Slow Blink  |
# | 5 | Purple       || \e[0;35m |          || \e[0;45m |           |    | 6 | Rapid Blink |
# | 6 | Cyan         || \e[0;36m |          || \e[0;46m |           |    | 7 | reverse     |
# | 7 | Light Gray   || \e[0;37m |          || \e[0;47m |           |     ---+-------------
# | 0 | Dark Gray    || \e[1;30m | \e[0;90m || \e[1;40m | \e[0;100m |     ---------------------
# | 1 | Light Red    || \e[1;31m | \e[0;91m || \e[1;41m | \e[0;101m |    |       others        |
# | 2 | Light Green  || \e[1;32m | \e[0;92m || \e[1;42m | \e[0;102m |     -------------+-------
# | 3 | Light Yellow || \e[1;33m | \e[0;93m || \e[1;43m | \e[0;103m |    | color none  | \e[0m |
# | 4 | Light Blue   || \e[1;34m | \e[0;94m || \e[1;44m | \e[0;104m |    | color reset | \e[1m |
# | 5 | Light Purple || \e[1;35m | \e[0;95m || \e[1;45m | \e[0;105m |     -------------+-------
# | 6 | Light Cyan   || \e[1;36m | \e[0;96m || \e[1;46m | \e[0;106m |     ----------------+---------------------------------
# | 7 | White        ||      \e[0;97m       ||      \e[0;107m       |    | \[\e[xx;0m]\]  | system color                    |
#  ---+--------------++---------------------++----------------------     | \[\e[xx\;0m]\] | system color in ``              |
# |   |              ||  \e[38;5;{0..255}m# ||  \e[48;5;{0..255}m#  |    | \[\e[0;xxm]\]  | profile color (solarized)       |
#  ---+--------------++---------------------++----------------------     | \[\e[0\;xxm]\] | profile color (solarized) in `` |
#                                                                         ----------------+---------------------------------
#  ------------+-------------------------------------------------------   ----------------+-------------------------------
# |                   256 colors standard format                       | |                   comments                     |
#  ------------+-------------------------------------------------------   ----------------+-------------------------------
# | attributes | 0 1 2 3 4 5 6 7                                       | | COL_NONE       | no color                      |
# | foregrand  | {0..255}                                              | | COL_RESET      | reset color                   |
# | background | {30..37} {90..97} 39                                  | | COL_DEFAULT    | default color                 |
#  ------------+-------------------------------------------------------  | COL_IF_DEFAULT | default color in if-statement |
# | usage : \e[${attributes};{background};5;${foreground}m <str> \e[0m |  ----------------+-------------------------------
#  ------------+-------------------------------------------------------
#
# Solarized color table from http://ethanschoonover.com/solarized.
#
# | SOLARIZED | HEX     | ANSI      | TERMCOL   | cmd.exe     | PowerShell  | ColorTable | DWORD    |
# |-----------|---------|-----------|-----------|-------------|-------------|------------|----------|
# | base03    | #002b36 | ESC[0;30m | brblack   | Black       | Black       | 00         | 00362b00 |
# | base02    | #073642 | ESC[1;30m | black     | Gray        | DarkGray    | 08         | 00423607 |
# | base01    | #586e75 | ESC[0;32m | brgreen   | Green       | DarkGreen   | 02         | 00756e58 |
# | base00    | #657b83 | ESC[0;33m | bryellow  | Yellow      | DarkYellow  | 06         | 00837b65 |
# | base0     | #839496 | ESC[0;34m | brblue    | Blue        | DarkBlue    | 01         | 00969483 |
# | base1     | #93a1a1 | ESC[0;36m | brcyan    | Aqua        | DarkCyan    | 03         | 00a1a193 |
# | base2     | #eee8d5 | ESC[0;37m | white     | White       | Gray        | 07         | 00d5e8ee |
# | base3     | #fdf6e3 | ESC[1;37m | brwhite   | BrightWhite | White       | 15         | 00e3f6fd |
# | yellow    | #b58900 | ESC[1;33m | yellow    | LightYellow | Yellow      | 14         | 000089b5 |
# | orange    | #cb4b16 | ESC[0;31m | brred     | Red         | DarkRed     | 04         | 00164bcb |
# | red       | #dc322f | ESC[1;31m | red       | LightRed    | Red         | 12         | 002f32dc |
# | magenta   | #d33682 | ESC[1;35m | magenta   | LightPurple | Magenta     | 13         | 008236d3 |
# | violet    | #6c71c4 | ESC[0;35m | brmagenta | Purple      | DarkMagenta | 05         | 00c4716c |
# | blue      | #268bd2 | ESC[1;34m | blue      | LightBlue   | Blue        | 09         | 00d28b26 |
# | cyan      | #2aa198 | ESC[1;36m | cyan      | LightAqua   | Cyan        | 11         | 0098a12a |
# | green     | #859900 | ESC[1;32m | green     | LightGreen  | Green       | 10         | 00009985 |

PS1="\[$(tput setaf 0) \]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 1) \]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 2) \]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 3) \]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 4) \]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 5) \]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 6) \]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 7) \]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 8) \]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 9) \]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 10)\]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 11)\]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 12)\]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 13)\]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 14)\]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 15)\]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 16)\]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 17)\]my prompt\[$(tput sgr0)\]> "
PS1="\[$(tput setaf 18)\]my prompt\[$(tput sgr0)\]> "

or ps1 with conditions

$ DEFAULT="\[$(tput setaf 3)\]"         # or '\[\033[1;38;5;3m\]'     or '\[\e[1;33m\]'
$ ifDEFAULT='\[\e[1\;33m\]'             # or '\[\033[1\;38\;5\;3m\]'
$ ifRED='\[\e[1\;31m\]'                 # or '\[\033[1\;38\;5\;1m\]'
$ PS1="${DEFAULT}my prompt${RESET} \$( if [ \$? != 0 ]; then echo -e ${ifRED}\\$; else echo -e ${ifDEFAULT}\\$; fi) ${RESET}"

functions

function showKeyMap() { RET=$?; bind -v | awk '/keymap/ {print $NF}'; return "${RET}"; }
function rightPrompt() {
  if [ "$(bind -v | awk '/keymap/ {print $NF}')" == 'emacs' ]; then
    kmap=⌁
  else
    kmap=⚙︎
  fi
  printf "%*s" $COLUMNS "${kmap}"
}

PS1+="- [\$(showKeyMap)] "
PS1+="- [\$(tput sc; rightPrompt; tput rc)]"

right prompt

rightprompt() { printf "%*s" $COLUMNS "right prompt"; }
PS1='\[$(tput sc; rightprompt; tput rc)\]left prompt > '

character

metacharacter

Character

Where

Meaning

<RETURN>

csh, sh

Execute command

#

csh, sh, ASCII files

Start a comment

<SPACE>

csh, sh

Argument separator

csh, sh

Command substitution

"

csh, sh

Weak Quotes

'

csh, sh

Strong Quotes

\

csh, sh

Single Character Quote

variable

sh, csh

Variable

variable

csh, sh

Same as variable

\

csh, sh

Pipe character

^

Pipe Character

&

csh, sh

Run program in background

?

csh, sh

Match one character

*

csh, sh

Match any number of characters

;

csh, sh

Command separator

;;

End of Case statement

~

csh

Home Directory

~user

csh

User's Home Directory

!

csh

History of Commands

-

Programs

Start of optional argument

$#

csh, sh

Number of arguments to script

$*

csh, sh

Arguments to script

$@

Original arguments to script

$-

Flags passed to shell

$?

Status of previous command

$$

Process identification number

$!

PID of last background job

&&

Short-circuit AND

||

Short-circuit OR

.

csh, sh

Typ. filename extension

.

Source a file and execute as command

:

Nothing command

:

Separates Values in environment variables

:

csh

Variable modifier

Character

Where

Meaning

[ ]

csh, sh

Match range of characters

[ ]

Test

%job

csh

Identifies job Number

(cmd;cmd)

csh. sh

Runs cmd;cmd as a sub-shell

{ }

csh

In-line expansions

{cmd;cmd }

Like (cmd;cmd ) without a subshell

>ofile

csh, sh

Standard output

>>ofile

csh, sh

Append to standard output

<ifile

csh, sh

Standard Input

<<word

csh, sh

Read until word, substitute variables

<<\word

csh, sh

Read until word, no substitution

<<-word

Read until word, ignoring TABS

>>!file

csh

Append to file, ignore error if not there

>!file

csh

Output to new file, ignore error if not there

>&file

csh

Send standard & error output to file

<&digit

Switch Standard Input to file

<&-

Close Standard Input

>&digit

Switch Standard Output to file

>&-

Close Standard Output

digit1<&digit2

Connect digit2 to digit1

digit<&-

Close file digit

digit2>&digit1

Connect digit2 to digit1

digit>&-

Close file digit

process substitution

[!TIP] Process substitution is a form of redirection where the input or output of a process (some sequence of commands) appear as a temporary file. reference:
chapter 23. process substitution Command list enclosed within parentheses
>(command_list)
<(command_list)
Process substitution uses /dev/fd/<n> files to send the results of the process(es) within parentheses to another process. [1]

$ while read branch; do
    git fetch --all --force;
  done < <(git rev-parse --abbrev-ref HEAD)

$ echo >(true)
/dev/fd/63
$ echo <(true)
/dev/fd/63

$ echo >(true) <(true)
/dev/fd/63 /dev/fd/62

$ echo <(date)
/dev/fd/63
$ cat <(date)
Tue Dec 15 22:32:08 CST 2020

named pipe similar

$ wc <(cat /usr/share/dict/words)
 235886  235886 2493109 /dev/fd/63
$ cat /usr/share/dict/words | wc
 235886  235886 249310

$ wc <(grep script /usr/share/dict/words)
    176     176    5414 /dev/fd/63
$ grep script /usr/share/dict/words | wc
    176     176    5414

# https://superuser.com/a/1059790/112396
$ cat file | while read line; do ((count++)); done
$ while read line; do ((count++)); done < <(cat file)

get diff in two folders

$ diff <(ls ibook) <(ls mbook)
1c1,2
< book.json
---
> _book
> book.json
3a5
> node_modules

$ diff <(sleep 4; date) <(sleep 5; date)
1c1
< Tue Dec 15 22:48:31 CST 2020
---
> Tue Dec 15 22:48:32 CST 2020

example: run script without download

$ bash < <(wget -qO - https://raw.githubusercontent.com/ubports/unity8-desktop-install-tools/master/install.sh)

via curl

$ python < <(curl -s https://raw.githubusercontent.com/giampaolo/psutil/master/scripts/meminfo.py)

$ curl -so - https://raw.githubusercontent.com/giampaolo/psutil/master/scripts/meminfo.py | python

via wget

$ python < <(wget -O - -q -t 1 https://raw.githubusercontent.com/giampaolo/psutil/master/scripts/meminfo.py)

$ wget -qO - https://raw.githubusercontent.com/giampaolo/psutil/master/scripts/meminfo.py | python

$ python < <(curl -s https://raw.githubusercontent.com/giampaolo/psutil/master/scripts/meminfo.py)
MEMORY
------
Total      :   16.0G
Available  :    5.8G
Percent    :    63.8
Used       :    8.8G
Free       :  204.5M
Active     :    5.4G
Inactive   :    5.6G
Wired      :    3.4G

SWAP
----
Total      :    1.0G
Used       :  269.2M
Free       :  754.8M
Percent    :    26.3
Sin        :   38.3G
Sout       :   63.9M

$ python < <(curl -s https://raw.githubusercontent.com/giampaolo/psutil/master/scripts/disk_usage.py)
Device               Total     Used     Free  Use %      Type  Mount
/dev/disk1s5        233.5G    10.6G    70.6G    13%      apfs  /
/dev/disk1s1        233.5G   149.6G    70.6G    67%      apfs  /System/Volumes/Data
/dev/disk1s4        233.5G     2.0G    70.6G     2%      apfs  /private/var/vm
/Library/Input Methods/SogouInput.app   233.5G   149.1G    71.1G    67%    nullfs  /private/var/folders/s3/mg_f3cv54nn7y758j_t46zt40000gn/T/AppTranslocation/E29031DE-FE63-4ABC-BA3D-E99C743E57D2

example: merge lines of file

inspired by here and here

$ cat a
t1
t2
t3
t4
$ cat b
11
22
33
44

$ paste <(cat a) <(cat b)
t1  11
t2  22
t3  33
t4  44

additional usage

$ cat a | paste -d'\t' - - - -
a b c d
e f

$ cat a | paste -d, - -
a,b
c,d
e,f

/dev/fd/63 is not a regular file

$ more <( ls -l )
/dev/fd/63 is not a regular file (use -f to see it)

$ more -f <( ls -l )
total 12
-rw-r--r--  1 marslo staff 3457 Nov  2 15:53 README.md
-rw-r--r--  1 marslo staff 4314 Nov  2 15:53 SUMMARY.md
drwxr-xr-x  6 marslo staff  192 Oct 12 22:10 artifactory
drwxr-xr-x  8 marslo staff  256 Sep 29 17:40 cheatsheet
drwxr-xr-x 12 marslo staff  384 Oct 15 15:27 devops
drwxr-xr-x  7 marslo staff  224 Sep 28 22:17 jenkins
drwxr-xr-x 11 marslo staff  352 Sep 28 22:17 kubernetes
drwxr-xr-x  8 marslo staff  256 Oct  9 19:15 linux
drwxr-xr-x  8 marslo staff  256 Nov  2 15:51 osx
drwxr-xr-x  6 marslo staff  192 Sep 28 22:17 programming
drwxr-xr-x 45 marslo staff 1440 Nov  2 13:56 screenshot
drwxr-xr-x 11 marslo staff  352 Oct 14 21:22 tools

nstalling tools via running random scripts from unknown sites

$ ( wget -O - pi.dk/3 || lynx -source pi.dk/3 || curl pi.dk/3/ || \
    fetch -o - http://pi.dk/3 ) > install.sh

basic commands

`du`

top biggest directories under [path]
```
$ du -a [path] | sort -n -r | head -n 5
```
display the largest files according to human-readable format
```
$ du -hs * | sort -rh | head -5
```
display the largest folders/files including the sub-directories
```
$ du -Sh | sort -rh | head -5
```

biggest file sizes

$ find -type f -exec du -Sh {} + | sort -rh | head -n 5

# or
$ find [PATH] -type f -printf "%s %p\n" | sort -rn | head -n 5

du with colored bar graph

$ t=$(df|awk 'NR!=1{sum+=$2}END{print sum}'); sudo du / --max-depth=1 | sed '$d' | sort -rn -k1 | awk -v t=$t 'OFMT="%d" {M=64; for (a=0;a<$1;a++){if (a>c){c=a}}br=a/c;b=M*br;for(x=0;x<b;x++){printf "\033[1;31m" "|" "\033[0m"}print " "$2" "(a/t*100)"% total"}'

sort

sort result via human-readable format

$ sudo du -ahx --max-depth=1 <path> | sort -k1 -rh

$ du -sk * | sort -g | awk '{

    numBytes = $1 * 1024;
    numUnits = split("B K M G T P", unit);
    num = numBytes;
    iUnit = 0;

    while(num >= 1024 && iUnit + 1 < numUnits) {
        num = num / 1024;
        iUnit++;
    }

    $1 = sprintf( ((num == 0) ? "%6d%s " : "%6.1f%s "), num, unit[iUnit + 1]);
    print $0;

}'

# or in one-line
$ du -sk * | sort -g | awk '{ numBytes = $1 * 1024; numUnits = split("B K M G T P", unit); num = numBytes; iUnit = 0; while(num >= 1024 && iUnit + 1 < numUnits) { num = num / 1024; iUnit++; } $1 = sprintf( ((num == 0) ? "%6d%s " : "%6.1f%s "), num, unit[iUnit + 1]); print $0; }'

#! /usr/bin/env bash
ducks () {
    du -cks -x | sort -n | while read size fname; do
        for unit in k M G T P E Z Y; do
            if [ $size -lt 1024 ]; then
                echo -e "${size}${unit}\t${fname}"
                break
            fi
            size=$((size/1024))
        done
    done
}
ducks > .ducks && tail .ducks

$ du -k ./* |
     sort -nr |
     awk '{ split("KB,MB,GB",size,","); }
          { x = 1;while ($1 >= 1024) {$1 = $1 / 1024;x = x + 1} $1 = sprintf("%-4.2f%s", $1, size[x]); print $0; }'

others

`you have new mail`

remove

$ mail
? delete *
No applicable messages.
? q

or
```
$ mail -N
? d *
? quit
```

crontab

[!NOTE|label:references:]
Linux / UNIX Crontab File Location
* cron.help | * cron analysis
cron examples
Cron Jobs: The Complete Guide for 2023

format

*    *    *    *    *   /home/user/bin/somecommand.sh
|    |    |    |    |            |
|    |    |    |    |    Command or Script to execute
|    |    |    |    |
|    |    |    | Day of week(0-6 | Sun-Sat)
|    |    |    |
|    |    |  Month(1-12)
|    |    |
|    |  Day of Month(1-31)
|    |
|   Hour(0-23)
|
Min(0-59)

tips
- every odd hours
  0 1-23/2 * * *
- every even hours
  0 */2 * * *

sample

delete .DS_

15 */2 * * 1-5 /usr/local/bin/fd --type f --hidden --follow --unrestricted --color=never --exclude .Trash --glob '*\.DS_*' $HOME | xargs -r rm
# or
30 */2 * * 1-5 /usr/local/bin/fd -Iu --glob '*\.DS_*' $HOME | xargs -r rm
# or
30 */2 * * 1-5 /usr/local/bin/rg --hidden --smart-case --color=never --files "$HOME" -g '*\.DS_*' | xargs -r rm

flush disk cache
```
0 * * * * /usr/sbin/purge
```

flush DNS

0 1-23/6 * * * /usr/bin/killall -HUP mDNSResponder

localtion

macos

$ sudo ls -Altrh /usr/lib/cron/tabs/<USERNAME>

freebsd/openbsd/netbsd

$ sudo ls -Altrh /var/cron/tabs/<USERNAME>

centos/rhel/fedora/scientific/rocky/alma linux
```
$ sudo ls -Altrh /var/spool/cron/<USERNAME>
```

debian/ubuntu/mint linux

$ sudo ls -Altrh /var/spool/cron/crontabs/<USERNAME>

p-ux unix

$ sudo ls -Altrh /var/spool/cron/crontabs/<USERNAME>

ibm aix unix

$ sudo ls -Altrh /var/spool/cron/<USERNAME>

tricky

references:
Searching the manual pages
How To Readline
Commandline Howto
Advanced Commandline Howto

unicode

references:
* iMarslo: Unicode | * iMarslo: unicode in vim/nvim
How do you echo a 4-digit Unicode character in Bash?
centos locale utf-8
How can I make iconv replace the input file with the converted output?
Your description is vague. Either your terminal does not support Unicode, or you're editing a file that's in latin1 (= iso-8859-1). On a bash or zsh shell, with LC_CTYPE=en_US.UTF-8, run echo $'\xc3a9'. If you see é, your terminal supports UTF-8. If you see Ã©, your terminal is showing latin1.

$ echo $'\xc3a9'
a9

$ echo $'\xe2\x98\xa0'
☠
$ echo $'(U+2620) \U02620' | /usr/bin/xxd
00000000: 2855 2b32 3632 3029 20e2 98a0 0a         (U+2620) ....

# test
$ for (( i=0x2500; i<0x2600; i++ )); do
  UnicodePointToUtf8 $i
  [ "$(( i+1 & 0x1f ))" != 0 ] || echo ""
done
─━│┃┄┅┆┇┈┉┊┋┌┍┎┏┐┑┒┓└┕┖┗┘┙┚┛├┝┞┟
┠┡┢┣┤┥┦┧┨┩┪┫┬┭┮┯┰┱┲┳┴┵┶┷┸┹┺┻┼┽┾┿
╀╁╂╃╄╅╆╇╈╉╊╋╌╍╎╏═║╒╓╔╕╖╗╘╙╚╛╜╝╞╟
╠╡╢╣╤╥╦╧╨╩╪╫╬╭╮╯╰╱╲╳╴╵╶╷╸╹╺╻╼╽╾╿
▀▁▂▃▄▅▆▇█▉▊▋▌▍▎▏▐░▒▓▔▕▖▗▘▙▚▛▜▝▞▟
■□▢▣▤▥▦▧▨▩▪▫▬▭▮▯▰▱▲△▴▵▶▷▸▹►▻▼▽▾▿
◀◁◂◃◄◅◆◇◈◉◊○◌◍◎●◐◑◒◓◔◕◖◗◘◙◚◛◜◝◞◟
◠◡◢◣◤◥◦◧◨◩◪◫◬◭◮◯◰◱◲◳◴◵◶◷◸◹◺◻◼◽◾◿

## test harness
$ for (( i=0x2500; i<0x2600; i++ )); do unichr $i; done
─━│┃┄┅┆┇┈┉┊┋┌┍┎┏┐┑┒┓└┕┖┗┘┙┚┛├┝┞┟┠┡┢┣┤┥┦┧┨┩┪┫┬┭┮┯┰┱┲┳┴┵┶┷┸┹┺┻┼┽┾┿╀╁╂╃╄╅╆╇╈╉╊╋╌╍╎╏═║╒╓╔╕╖╗╘╙╚╛╜╝╞╟╠╡╢╣╤╥╦╧╨╩╪╫╬╭╮╯╰╱╲╳╴╵╶╷╸╹╺╻╼╽╾╿▀▁▂▃▄▅▆▇█▉▊▋▌▍▎▏▐░▒▓▔▕▖▗▘▙▚▛▜▝▞▟■□▢▣▤▥▦▧▨▩▪▫▬▭▮▯▰▱▲△▴▵▶▷▸▹►▻▼▽▾▿◀◁◂◃◄◅◆◇◈◉◊○◌◍◎●◐◑◒◓◔◕◖◗◘◙◚◛◜◝◞◟◠◡◢◣◤◥◦◧◨◩◪◫◬◭◮◯◰◱◲◳◴◵◶◷◸◹◺◻◼◽◾◿

# https://stackoverflow.com/a/55639328/2940319
$ echo -e "\U1F304"
�
$ echo -e "�" | /usr/bin/hexdump -C
00000000  f0 9f 8c 84 0a                                    |.....|
00000005

unicode to utf8

UnicodePointToUtf8() {
  local x="$1"                   # ok if '0x2620'
  x=${x/\\u/0x}                  # '\u2620' -> '0x2620'
  x=${x/U+/0x}; x=${x/u+/0x}     # 'U-2620' -> '0x2620'
  x=$((x)) # from hex to decimal
  local y=$x n=0
  [ $x -ge 0 ] || return 1
  while [ $y -gt 0 ]; do y=$((y>>1)); n=$((n+1)); done
  if [ $n -le 7 ]; then          # 7
      y=$x
  elif [ $n -le 11 ]; then       # 5+6
      y=" $(( ((x>> 6)&0x1F)+0xC0 )) \
          $(( (x&0x3F)+0x80 ))"
  elif [ $n -le 16 ]; then       # 4+6+6
      y=" $(( ((x>>12)&0x0F)+0xE0 )) \
          $(( ((x>> 6)&0x3F)+0x80 )) \
          $(( (x&0x3F)+0x80 ))"
  else                           # 3+6+6+6
      y=" $(( ((x>>18)&0x07)+0xF0 )) \
          $(( ((x>>12)&0x3F)+0x80 )) \
          $(( ((x>> 6)&0x3F)+0x80 )) \
          $(( (x&0x3F)+0x80 ))"
  fi
  printf -v y '\\x%x' $y
  echo -n -e $y
}

unichr

fast_chr() {
  local __octal
  local __char
  printf -v __octal '%03o' $1
  printf -v __char \\$__octal
  REPLY=$__char
}

function unichr {
  local c=$1  # Ordinal of char
  local l=0   # Byte ctr
  local o=63  # Ceiling
  local p=128 # Accum. bits
  local s=''  # Output string

  (( c < 0x80 )) && { fast_chr "$c"; echo -n "$REPLY"; return; }

  while (( c > o )); do
    fast_chr $(( t = 0x80 | c & 0x3f ))
    s="$REPLY$s"
    (( c >>= 6, l++, p += o+1, o>>=1 ))
  done

  fast_chr $(( t = p | c ))
  echo -n "$REPLY$s"
}

useful functions

universal extract

function extract () {
  case $1 in
    *.tar.bz2 ) tar xjf  "$1" ;;
    *.tar.gz  ) tar xzf  "$1" ;;
    *.tar.xz  ) tar Jxvf "$1" ;;
    *.tar.Z   ) tar xzf  "$1" ;;
    *.tar     ) tar xf   "$1" ;;
    *.taz     ) tar xzf  "$1" ;;
    *.tb2     ) tar xjf  "$1" ;;
    *.tbz     ) tar xjf  "$1" ;;
    *.tbz2    ) tar xjf  "$1" ;;
    *.tgz     ) tar xzf  "$1" ;;
    *.txz     ) tar Jxvf "$1" ;;
    *.zip     ) unzip    "$1" ;;
    *.gz      ) gunzip   "$1" ;;
    *         ) echo "'$1' cannot be extracted" ;;
  esac
}

up to parent folder

$ up() { local x=''; for i in $(seq ${1:-1}); do x="$x../"; done; cd $x; }

# usage
$ up
$ up 3

generate cron time format

# 2 minutes in the future
$ echocron () { date '-d +2 minutes' +'%M %k %d %m *'; }

search manual page

whatis -r <string>
apropos -r <string>

show services

$ systemctl list-unit-files -t service

Previoustricky Nextdevenv

Last updated 8 months ago

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