• https://ss64.com/bash/syntax-keyboard.html
• $ info readline
• https://git.savannah.gnu.org/cgit/readline.git/tree/doc/rluserman.info
• man termios

It's basically a device (implemented in software nowadays)

Ctrl+- undo

Ctrl+[ = Escape Ctrl+I = Tab Ctrl+M = Enter

Alt+/ = autocompletion for path Ctrl+J = Newline Ctrl+v tells the terminal to not interpret the following character, so Ctrl+v Ctrl-I will display a tab character, similarly Ctrl+v ENTER will display the escape sequence for the Enter key: ^M

Ctrl + C SIGINT, Break command Ctrl + Z in background, commands: jobs, fg, bg Ctrl + D SIGTSTP, logout Ctrl + \ SIGQUIT

Ctrl + XX toggle cursor from current position to begining and back Alt+U/L to UPPER/LOWER case word Alt+C upper first letter of word

Ctrl/Alt + D: Delete one char/to end of word starting at the cursor

Ctrl + u/k erase line to begining/end of line Ctrl + w cut word before cursor Alt + k cut word before cursor Alt + b cut word after cursor Ctrl+y yank

Ctrl+N/P loop commands Ctrl+S Stops all output on-screen (XOFF). Ctrl+Q Turns all output stopped on-screen back on (XON). Also, closes an application window.

!! Repeats the line last entered at the shell. !$ Repeats the last argument for the command last used. See history command for previous commands.

Alt+SysRq+r Unraw Take control of keyboard back from X. 4 Alt+SysRq+e Terminate Send SIGTERM to all processes, allowing them to terminate gracefully. 64 Alt+SysRq+i Kill Send SIGKILL to all processes, forcing them to terminate immediately. Alt+SysRq+s Sync Flush data to disk. 16 - Alt+SysRq+u Unmount Unmount and remount all filesystems read-only. 32 - Alt+SysRq+b Reboot Reboot 128 Alt+SysRq+k SAK Alt+SysRq+f OOM kill Alt+SysRq+j Thaw

X Ctrl+Alt+F1, F2, F3, … Switch to n-th virtual console If it does not work, try Ctrl+Alt+Fn+F…. Shift+Insert Paste text from the PRIMARY buffer

M-O in console activates when some key is pressed and holded for some time

https://unix.stackexchange.com/questions/4126/what-is-the-exact-difference-between-a-terminal-a-shell-a-tty-and-a-con https://dev.to/napicella/linux-terminals-tty-pty-and-shell-192e https://www.oreilly.com/library/view/linux-device-drivers/0596005903/ch18.html https://en.wikipedia.org/wiki/POSIX_terminal_interface https://habr.com/ru/post/460257/ https://medium.com/securitythread/linux-terminal-subsystem-d000475c8dd www.embeddedlinux.org.cn/essentiallinuxdevicedrivers/final/ch06lev1sec4.html

tty - teletypewriter https://en.wikipedia.org/wiki/Teleprinter

• terminal - became a computer program in the kernel which would send characters directly to the TTY driver, read from it and print to the screen.
  • is a character-oriented device, comprising streams of characters received from and sent to the device, dev/tty - device which implements a number of additional commands (ioctls) beyond read and write.
  • consist of:
    • character device interface ( open, read, write, close …)
    • Line discipline
    • driver - keyboard IO, display
  • may be: kernel program or pseudo terminal or serial device (old)
  • communicate with the terminal through terminal character device file
• terminal emulator - the kernel program emulate the physical terminal device. it listens for events coming from the keyboard and sends it down to the driver
• pseudo-terminal (pty) - provided by terminal emulators - it's not a kernel program but one that runs in the user land.
• System console - interface more
  1. physical device consisting of a keyboard and a screen
  2. text entry and display device for system administration messages
• Virtual console/virtual terminal - Ctrl+Alt+F1234
  • On each virtual terminal, a getty process is run, which in turn runs /bin/login to authenticate a user.
  • supported at the Linux kernel level
  • are emulated text terminals, using the keyboard and monitor of a personal computer or workstation
• terminal monitor program spawns (sets TERM env - Specifies the terminal type.)
  • may be:
    • getty TERM=linux
    • SSH server ( to the same terminal type as the SSH client)
    • software terminal emulator, using a pseudoterminal ( sets the TERM environment variable to specify the type of terminal that it is emulating)
      • GNU Screen program sets screen as the terminal type.
• shell - user space app
• escape code - . Certain sequences of bytes, most starting with an ASCII escape character and a bracket character, are embedded into text to control cursor location, color, font styling, and other options on video text terminals and terminal emulators.
  • man console_codes - Linux console escape and control sequences

Terminal emulator(get keys and draw gui) -> PTY master -> tty driver(with line discipline) -> pty slave -> bash

По умолчанию TTY устройство работает в каноничном режиме с включенным эхо (echoing). Эхо — это отображение введенных вами символов на экране.

GNU Readline - library that provides in-line editing and history capabilities - supports both Emacs and vi editing modes

terminfo - used by TERM enveronmental variable. which strings to send for clear screen, move cursor, etc.

• database: /usr/share/terminfo/*/* - /etc/terminfo/*/*
• default = /etc/terminfo/l/linux

agetty - opens a tty port

• who
• w
• last
• tty
• ps
• stty - change terminal settings, prints baud rate, line discipline, and deviations from stty sane
  • stty -a - get all
  • stty icanon -echo - disable echo
  • stty raw echo
  • stty <control-character> <string>
  • stty erase 0
• reset - reset terminal after cat binary file
• infocmp - compare or print out terminfo descriptions

The escape codes received from the terminal signify things such as function key, arrow key, and other special keystrokes (home key, end key, help key, PgUp key, PgDn key, insert key, delete key, and so forth)

The multiplexor is the master, and the PTS are the slaves. The multiplexor is addressed by the kernel through the device file located at /dev/ptmx.

https://www.computernetworkingnotes.com/linux-tutorials/linux-virtual-console-and-terminal-explained.html https://www.howtogeek.com/428174/what-is-a-tty-on-linux-and-how-to-use-the-tty-command/

• tmux

1. emerge x11-misc/xsel
   • bind '"\C-p": "\C-e\C-u xsel <<"EOF"\n\C-y\nEOF\n\C-y"'
2. emerge x11-misc/xclip
   • cat a | xclip -sel clip

ubuntu: apt install console-keymaps

• loadkeys /usr/share/keymaps/i386/dvorak/dvorak.kmap.gz

0 ^@    \0      Null
1 ^A            Start of Heading
2 ^B            Start of Text
3 ^C            End of Text
4 ^D            End of Transmission
5 ^E            Enquiry
6 ^F            Acknowledgement
7 ^G    \a      Bell
8 ^H    \b      Backspace[e][f]
9 ^I    \t      Horizontal Tab[g]
10 ^J   \n      Line Feed
11 ^K   \v      Vertical Tab
12 ^L   \f      Form Feed
13 ^M   \r      Carriage Return[h]
14 ^N           Shift Out
15 ^O           Shift In
16 ^P           Data Link Escape
17 ^Q           Device Control 1 (often XON)
18 ^R           Device Control 2
19 ^S           Device Control 3 (often XOFF)
20 ^T           Device Control 4
21 ^U           Negative Acknowledgement
22 ^V           Synchronous Idle
23 ^W           End of Transmission Block
24 ^X           Cancel
25 ^Y           End of Medium
26 ^Z           Substitute
27 ^[   \e[i]   Escape[j]
28 ^\           File Separator
29 ^]           Group Separator
30 ^^           Record Separator
31 ^_           Unit Separator

32 space
33 !    Exclamation mark
34 "    Double quotes (or speech marks)
35 #    Number sign
36 $    Dollar
37 %    Per cent sign
38 &    Ampersand
39 '    Single quote
40 (    Open parenthesis (or open bracket)
41 )    Close parenthesis (or close bracket)
42 *    Asterisk
43 +    Plus
44 ,    Comma
45 -    Hyphen-minus
46 .    Period, dot or full stop
47 /    Slash or divide
48 0
49 1
50 2
51 3
52 4
53 5
54 6
55 7
56 8
57 9
58 :    Colon
59 ;    Semicolon
60 <    Less than (or open angled bracket)
61 =    Equals
62 >    Greater than (or close angled bracket)
63 ?    Question mark
64 @, `, @      At sign
65 A
66 B
67 C
68 D
69 E
70 F
71 G
72 H
73 I
74 J
75 K
76 L
77 M
78 N
79 O
80 P
81 Q
82 R
83 S
84 T
85 U
86 V
87 W
88 X
89 Y
90 Z
91 [    Opening bracket
92 \, ~, \      Backslash
93 ]    Closing bracket
94 ↑, ^ Caret - circumflex
95 ←, _ Underscore
96 @, ` Grave accent
97 a
98 b
99 c
100 d
101 e
102 f
103 g
104 h
105 i
106 j
107 k
108 l
109 m
110 n
111 o
112 p
113 q
114 r
115 s
116 t
117 u
118 v
119 w
120 x
121 y
122 z
123 {   Opening brace
124 ACK, ¬, |   Vertical bar
125 }   Closing brace
126 ESC, |, ~   Equivalency sign - tilde
127 DEL Delete

sessions:

• tmux new-session -d top
• tmux ; C-b ( - switch to background session with top
• C-b ) ; C-d - deattach from background session

${ varname } is general syntax for $variable

• $_ At shell startup, set to the pathname used to invoke the shell or shell script being executed
• $1 - first parameter
• $#: How many command line parameters were passed to the script.
• $?: The exit status of the last process to run.
• $$: The Process ID (PID) of the current script.
• $* is a single string that consists of all of the positional parameters, separated by the first character in the environment variable IFS
• $@: All the command line parameters passed to the script. Cat be set: $set – 1 2 3
• $USER: The username of the user executing the script.
• $HOSTNAME: The hostname of the computer running the script.
• $SECONDS: The number of seconds the script has been running for.
• $RANDOM: Returns a random number.
• $LINENO: Returns the current line number of the script.
• IFS (internal field separator), which is a space, TAB, and NEWLINE by default.
• env | less # environment variables

my=Dave my="Dave Green" file_count=$(ls $folder_to_count | wc -l) # miltiline

export mt_var # to save variables to outside of the script

multiline variable (heredoc):

method1="This is line no.1\nThis is line no.3\nThis is line no.3"
echo -e $method1


read -r -d '' MULTI_LINE_VAR << EOM
Print line 1.
Print line 2.
Print line 3
EOM

• ( set -o posix ; set ) | less
• env
• printenv - same as env

• ls *{txt,log} list all files ending with txt or log in the current directory
• cp ~/projects/adders/verilog/{half_,full_}adder.v . copy half_adder.v and full_adder.v to current directory
• mv story.txt{,.bkp} rename story.txt as story.txt.bkp
• cp story.txt{,.bkp} to create bkp file as well retain original
• mv story.txt{.bkp,} rename story.txt.bkp as story.txt
• mv story{,_old}.txt rename story.txt as story_old.txt
• touch file{1..4}.txt same as touch file1.txt file2.txt file3.txt file4.txt
• touch file_{x..z}.txt same as touch file_x.txt file_y.txt file_z.txt
• rm file{1..4}.txt same as rm file1.txt file2.txt file3.txt file4.txt
• echo story.txt{,.bkp} displays the expanded version 'story.txt story.txt.bkp' , useful to dry run before executing actual command

• ?(pattern-list) Matches zero or one occurrence of the given patterns
• *(pattern-list) Matches zero or more occurrences of the given patterns
• +(pattern-list) Matches one or more occurrences of the given patterns
• @(pattern-list) Matches one of the given patterns
• !(pattern-list) Matches anything except one of the given patterns

sheck if enabled:

$ shopt extglob
extglob            on

ex.

$ ls !(*.txt)
main.c  math.h  power.log

standard streams == file descriptors

Commands has:

• 0 <- terminal
• 1 -> terminal
• 2 -> terminal

get length

${#my_string}

• echo '$(echo "upg")' = > $(echo "upg")
• echo "$(echo "upg")" = > upg
  • The special parameters * and @ have special meaning when in double quotes in special cases
• a="as\nasd $BASH $(echo wtf)(new line)"
• a='as\nasd $BASH $(echo wtf)(new line)'
  • echo $a => as\nasd $BASH $(echo wtf)
  • echo "$a" => as\nasd $BASH $(echo wtf)(new line)
  • echo -e $a => as(new line)asd $BASH $(echo wtf)
  • echo -e "$a" => as(new line)asd $BASH $(echo wtf)(new line)
  • printf '%q\n' "$a" => $'as\\nasd $BASH $(echo wtf)\n'

general

• cat
• sed
• grep
• awk - excellent slicer and more
• perl/python

special

• sort
• head/tail
• cut
• xargs - convert several lines to one line
• uniq
• cmp/diff
• tr replace characters
• nl number lines of files
• paste merge lines of files
• rev reverse lines characterwise
• fold
• shuf get random lines
• for item in list; do command $item done
• expand and unexpand: convert between tabs and spaces
• cut print part of each line of file separated by TAB or delimiter
• paste and join: read two files into one
• fmt, pr, fold, column, nl : text formatting

• top 2.24
• ps 2.23
• kill/killall/pkill
• free
• pgrep
• fg - background child processes
• jobs
  • -l list
  • -p process numbers

background

• nohup command & - even after exiting the shell
• timeout 15 command &
• ( sleep 1000 & ) - deattached from bash

Which process block file/folder?

• ls -l /proc/*/fd/* | grep ~/Downloads
• lsof/lsfd -l ~/Downloads
• fuser Downloads

$! - get pid of last started background child proces

see 2.10.13

help set

Using + rather than - causes these flags to be turned off.

The current set of flags:

echo $- # himBHs

• – Assign any remaining arguments to the positional parameters.
• - Assign any remaining arguments to the positional parameters.
• -e Exit immediately if a command exits with a non-zero status.
• -u Treat unset variables as an error when substituting.
• -f Disable file name generation (globbing). disables filename expansion also known as globbing.
• -o pipefail exit execution if one of the commands in the pipe fails.
• -v Print shell input lines as they are read.
• -x Print commands and their arguments as they are executed.
• -C If set, disallow existing regular files to be overwritten by redirection of output
• -T If set, the DEBUG and RETURN traps are inherited by shell functions.

set -e may result in some difficult to debug issues during loops because a failed command will only exit the subshell created by the pipe

directory - flat file that maps an name to inode on the filesystem.

• ls -al -tr - sort by time, reversal (latest at the bottom) (desc)
• ls * - directories and their files/folders - deep 1
• ls -d */ - only directories
• ls -d .* - dot files
• ls -d /home/user/{,.} - directories and all files, include hidden with full path
• ls -F appends symbols to filenames */=>@|
  • @ means symbolic link (or that the file has extended attributes).
  • * means executable.
  • = means socket.
  • | means named pipe.
  • > means door.
  • / means directory.

output in columns with classify

l='ls -F --color' ; paste -d: <($l | grep '/$') <($l | grep '*$') <($l | grep '@$') <($l | grep -v '[/@*]$') | tac| column -t -s ":" -N FOLDERS,EXECUTABLES,LINKS,OTHER

• dirs -v - to print stack
• dirs - cd history without pushd/popd.
  • dirs +0 - current directory
  • dirs +1 - last directory
  • ~1 = dirs +1
  • ~-0 dirs -0 - first directory in history

https://www.howtogeek.com/659146/how-to-use-pushd-and-popd-on-linux/

#!/usr/bin/env bash

set -euxo pipefail

in bash . and source equal in POSIX:

• ./script creates a new shell and executes each command in the script within the new shell. When the end of the script file is encountered, the new shell exits. Any changes in the new shell caused by the script are lost when the shell exits. (no screen formations)
• source execute a shell script within the context of the current shell. Since execution takes place within the context of the current shell, any changes in the shell are retained following the completion of the shell. (like by yourself)
• . script - in the current shell without forking a sub shell (equal to source)
• exec ./script - exit shell after finish

The exec command will execute a command in place of the current shell, that is, it terminates the current shell and starts a new process in its place.

exec was often used to execute the last command of a shell script. This would kill the shell slightly earlier; otherwise, the shell would wait until the last command was finished. This practice saves a process and some memory.

try exec ls. you will be logged out from your login shell.

let m=(4 * 1024) echo $((2*2)) ((m-=3)) # m=m-3 ((m++)

the let command is not specified by POSIX®. The portable alternative is: [ "$(( <EXPRESSION> ))" -ne 0 ]

echo $((2#010)) - binary to decimal

expr

• is command should be preffered
• cannot assign directly to bash variables but instead returns a result on stdout
• takes each operator it recognizes as a separate word and then concatenates them into a single expression that's evaluated according to it's own rules (which differ from shell arithmetic).

$() or ``

. file == source file - execute commands in file in current shell. no need x right ./file - execute file - need x right

$( ) has the side-effect of removing trailing newlines from the results.

• -0, –null - Input items are terminated by a null character instead of by whitespace - file or directory names containing spaces or newlines are correctly handled
• transfer input to one line usable as arguments (default echo)
• xargs -n 2 # execute command for every two argument, ex diff

ex

• find /path -name '*.foo' | xargs -P 24 -I '{}' /cpu/bound/process '{}' -o '{}'.out
  • -P n - Run up to max-procs processes at a time
• cat lines | xargs | tr ' ' ',' => line1,line2,line3,line4

with timestamp echo 'export HISTTIMEFORMAT="%d/%m/%y %T "' >> ~/.bash_profile

get user id

https://www.math.utah.edu/docs/info/diff_3.html

• default
• “Copied” context with -c
• “Unified” context with -u Instead of displaying the two files separately, it merges them together.

diff one two

Default context - no longer widely used (used by git)

• `8a12,15' (lar) - after line 8 of one append lines 12-15 of two.
• '5,7c8,10' (fct) - change lines 5–7 of one to read as lines 8–10 of two
• `5,7d3' (rdl) - delete lines 5–7 of one (which at 3 in two)
• < - in one
• > - in two

“Copied” context - has context lines without pre-symbols

• '!' - changing like
• '+' - line of two file (nothin in one)
• '-' - line of one file (nothin in two)

“Unified” context - more compact because it omits redundant context lines. GNU patch can apply this format.

• * from-file from-file-modification-time
• — to-file to-file-modification time
• @@ from-file-range to-file-range @@
• '+' line of two file
• '-' line of one file

Differences Side by Side diff -y :

• `|' The corresponding lines differ, and they are either both complete or both incomplete.
• `<' The files differ and only the first file contains the line.
• `>' The files differ and only the second file contains the line.
• `(' Only the first file contains the line, but the difference is ignored.
• `)' Only the second file contains the line, but the difference is ignored.
• `\' The corresponding lines differ, and only the first line is incomplete.
• `/' The corresponding lines differ, and only the second line is incomplete.

• date +%c –date "2022-06-20" => Mon Jun 20 00:00:00 2022
• date +%F –date='@2147483647' => 2038-01-19
• date –date '06/02/2016 09:01:39' +"%s" => 1464872499
• date +%s => 1656480511

https://www.computernetworkingnotes.com/linux-tutorials/ps-aux-command-and-ps-command-explained.html

a:- This option prints the running processes from all users. u:- This option shows user or owner column in output. x:- This option prints the processes those have not been executed from the terminal.

ps –eo pid,user,%cpu,cmd –-sort=-%cpu | head –n 4 ps –A –forest

notes:

• CPU usage is expressed as the percentage of time spent running during the entire lifetime of a process.
• The SIZE and RSS fields don't count some parts of a process including the page tables, kernel stack, struct thread_info, and struct task_struct.
• SIZE is the virtual size of the process (code+data+stack).
• Processes marked <defunct> are dead processes (so-called "zombies") that remain because their parent has not destroyed them properly.
• If the length of the username is greater than the length of the display column, the username will be truncated.

PID of the bash script you can use variable $$

include uptime command

top -d 0.5 # faster
cat /proc/loadavg

sort:

• ps -o RES
• ps -o +%MEM
• f - Field manager
  • s - current sort field,
  • q - quit

control:

• ? - help
• parent-child - V key
• kill: press k and enter PID
• bold/colur - b/z
• renice - r
• </> - sort by column

memory:

• %MEM: The percentage of the system’s physical memory in use by this process
• VIRT: Virtual memory size
• RES: Resident set size: the total physical memory in use by this process

sort by VIRT memory

for i in {1..10};do date; top -b -o +VIRT | head -n 17|tail -11;sleep 5;done

get all processed by name and kill them

pgrep python | xargs kill -s 9

https://www.howtogeek.com/425232/how-to-securely-delete-files-on-linux/

Since last reboot

vmstat 2 -d -S M

• 2 sec recreate

• -a - active and inactive memory
• -f - shows the number of tasks that have been launched
• -d - disk
• -D - summary statistics for your disk activity
• -p sda1

report memory map of a process

pmap -x $(pidof bash | cut -d ' ' -f 1) | head -n-2 | tail -n+3 | grep -v deleted | sort -k2 -n | awk '{sum+=$2} END {print sum/1024 " MiB"}'

find files by name and execute command:

• find . -type f -name "*.txt" -exec ls -l {} +
• find . -type f -name "*.txt" | xargs ls -l
• find . -type f -name "*.txt" -exec mv {} {}.old \;

multiple file extensions:

• find . -type f \( -name "*.sh" -o -name "*.txt" \)

find directory:

• find . -type d -iname So* -ls
  • -ls - print in ls -al format

• lsattr
• chattr
• chmod
• chown
• stat

• lsblk -p - list block devices, find connected USB Flash
• parted - partition table
  • parted -l - list partitions on all disks
• fdisk - partition table
  • fdisk -l
• dd
  • status=progress - useful to see what's happening
• sync - Synchronize cached writes to persistent storagem, when u write to USB

• tune2fs -l /dev/sdb2
• file -s /dev/sda1
• stat -fc %s .
• blockdev –getbsz /dev/sda # change when mounted

tar.gz:

• crate: tar -czf a.tar.gz /
• extract: tar xpzf –xattrs-include=' .' –numeric-owner a.tar.gz
  • -p, –preserve-permissions (default for supe ruser)
• inspect: tar ztf/tf m.tar.gz/m.tar
• create from files: tar –totals -cvf a.tar file1 file2 file3

TOP for texts:

• 7z - LZMA compression algorithm
• xz
• bzip2 - BWT
• rar
• gzip - LZ77
• zip

TOP for mixed:

• rar
• 7z
• zip
• bzip2
• gzip

my for texts 518MB :

• time tar.xz - real 1m49.582s, user 1m50.062s - 44M
• time tar.7z - real 0m55.497s, user 1m43.210s - 44M
• time tar.bz2 - real 0m33.160s, user 0m31.348s - 48M
• time tar.gz - real 0m10.430s, user 0m8.876s - 59M

texts < 14370 chars:

cat file  | gzip -f - |base64 | base64 -d | gzip -d -

for text > 14370 chars:

cat file  | bzip2 |base64 | base64 -d | bzip2 -d

• proxy support
• user authentication
• ftp upload
• SSL connections
• cookies
• file transfer resume and more

du -h -x -s – * | sort -r -h | head -20 - biggest files

man tcpdump | less -Ip examples

• I - IGNORE-CASE
• p - pattern

set time:

• date +%Y%m%d -s "20220429"
• date -s "19:35"

epoch to time:

• date -d @1234567890

append line to file and to STDOUT

echo "as" | tee -a /etc/fstab

• real - time from start to finish of the call.
• user - amount of CPU time spent in user-mode code (outside the kernel) within the process. This is only actual CPU

time used in executing the process.

• Sys - is the amount of CPU time spent in the kernel within the process.

other explanation.

• Real time is wall clock time. (what we could measure with a stopwatch)
• User time is the amount of time spend in user-mode within the process
• Sys is the CPU time spend in the kernel within the process.

Wall time, or the amount of time that passes between you starting the process and the process ending.

(Wall time) - (CPU time) = (time the CPU spent doing other things)

cases

• real < user: The process is CPU bound and takes advantage of parallel execution on multiple cores/CPUs.
• real ≈ user: The process is CPU bound and takes no advantage of parallel exeuction.
• real > user: The process is I/O bound. Execution on multiple cores would be of little to no advantage.

files opende by processes of user: lsfd -Q 'USER == "larry"'

find process on port:

fuser -nv tcp 80

• мониторинга процессов (ps, top, htop, atop, lsof)
• проверок производительности системы (nmon, iostat, sar, vmstat)
• утилитами диагностики сетевых подключений (ping, traceroute, mtr, nmap, netstat, tcpdupm, dig, scp),
• файрволов Linux (ufw/firewalld, iptables/nftables)

• print column:
  • ps | awk '{print $2}'
  • ps | tr -s ' ' | cut -d ' ' -f 3
• find duplicated files:
  • find ./ -type f -exec md5sum '{}' ';' > dupl
  • cat dupl | sort | uniq –all-repeated=separate -w 15 | grep '\.\/' | uniq -w 15 | cut -c 35- | xargs rm
• copy files from stdinput | xargs -I{} cp -u {} /destination/path
• rename multiple files: find . -depth -name "*.html" -exec sh -c 'f="{}"; mv – "$f" "${f%.html}.php"' \;

• sync directories: # rsync -aqxP /var/* /mnt/newvar
• вывод в файл и stdout: cmd | tee file
• list directories: ls -d */
• read file line by line: while read -r line;do echo "$line";done < file
• message window: xmessage -timeout 50 "MESSAGE HERE!!!"
• execute for every file: find . -name "*.jpg" -maxdepth 1 -type f -exec ~/firef \{\} \; -exec sleep 1 \; -exec pkill firefox \;
  • find . -name "*.mpg" -maxdepth 1 -type f -exec sh -c "firefox {} & sleep 10 ; pkill firefox ;" \;
  • for f in *.txt; do echo "$f"; done
• zip
  • for f in ./* ; do zip -r "${f:2}".zip "${f:2}" ; done # all folders
  • for f in ./* ; do zip -r "${f:2}".zip "$f" ; done # all files

time elapsed

SECONDS=0 ;  while true ; sleep 1 ; do echo -ne "\r" $SECONDS ; done

get parent process

• ps -o ppid= -p 21509
• pstree -s -p 21509

filename filepath

• basename $fspec # get filename
• dirname $fspec # get filedir

split and rejoin big file

• split -d -b 1M file file_prefix_
  • -b 1M put SIZE bytes per output file
  • -d use numeric suffixes starting at 0, not alphabetic
• cat file_prefix_* > file

logs from several host to one file

• node:

script -c 'python param.py' |& sed -u "s/^/${who}: /" |& perl -ne 'use IO::Handle ; printf "%s %s",  scalar time(), $_ ; STDOUT->autoflush(1) ;' |& tee -a ${who}.log

• server:

watch "cat chief_0.log worker_0.log worker_1.log | sort -ns -k1 | tail"

add string to every line in pipeline:

• <command> | sed 's/^/<string>/'
• <command> | awk '{print "<string>" $0}'
• <command> | while read line; do echo "<string>$line"; done

overwrite output

echo -en "aaaa\r" ; sleep 1 ; echo -ne "bbb\033[0K\r" ; sleep 1; echo "[INFO] Processing file: log.txt"

telega most frequient spammers

• cat messages.org | grep -o "@[^$ ]*" | grep -v '>' | sort | uniq -c | sort -r

replace substring in files

for f in ./*.el ; do
    cat $f | sed 's/2023/2024/g' > /tmp/t
    mv /tmp/t $f
done

split long lines, broke line with limit

echo 'asdasd' | fold -s -w 80

• https://learnbyexample.gitbooks.io/linux-command-line/content/Shell.html
• Shell & Utilities https://pubs.opengroup.org/onlinepubs/9699919799/utilities/contents.html
• https://github.com/dylanaraps/pure-bash-bible

extract IP:PORT from file:

• grep -E -o "([0-9]{1,3}[\.]){3}[0-9]{1,3}:[0-9]{1,5}" p.txt

• http://mywiki.wooledge.org/Bashism
• https://www.gnu.org/software/bash/manual/html_node/Bash-POSIX-Mode.html

[10] 0: bash*

• 10 - session number
• bash - window name, default is dynamic from current command name

server

Servers are terminated when the last remaining running session is closed.

session

default session with number 0. When we start a new instance of tmux, new session is created inside the running server.

window

pane

splits of window, pseudoterminals. Window always have at least one pane.

target-session (-t)

Ctrl-b is the begining of commands:

• ? help
• [ now Page Up, Page down
• CTRL+SPACE to start copying
• ALT+w or CTRL+w to copy into Tmux buffer.
• ] to paste

quit:

• x kill the current panel and quit if one left in window
• & kill window and quit
• d disconnect from panel

toggle between:

• (/) toggle between sessions
• s list sessions, x - kill session, C-p/n - up/down
• w list sessions and windows
• % create a horizontal pane
• " create a vertical pane
• o toggle between panes - current surround with green lines
• array toggle between panes
• L

rename:

• $ session
• , window
• https://danielmiessler.com/study/tmux/

• tmux ls - list tmux sessions
• tmux attach -t 0 - attach to session
• tmux

To start terminal with tmux:

xfce4-terminal -e tmux

To kill unused terminal windows with idling single bash:

alias cl="ps aux | grep '\-bash' | grep Ss+ |  tr -s ' ' | cut -f 2 -d ' ' | xargs kill -s 9"

to kill deattached tmux sessions, add to ~/.bashrc,

test -n "$DISPLAY" && tmux list-sessions | grep -v attached | cut -d: -f1 |  xargs -r -n1 tmux kill-session -t &>/dev/null

Soltuion: create file ~/tmux.conf and add this line:

set -s copy-command "xclip -sel clip -i"

this app should be installed:

emerge x11-misc/xclip

tmux list-sessions | grep -v attached | cut -d: -f1 |  xargs -r -n1 tmux kill-session -t &>/dev/null

global options:

tmux show-options -g

For window options:

tmux show-options -w

For server options:

tmux show-options -s

tmux list-keys | less

bind-key -T copy-mode C-k    send-keys -X cursor-up
bind-key -T copy-mode C-l    send-keys -X cursor-left

• /etc/ssh/sshd_config - server conf
  • /etc/conf.d/sshd
  • etc/ssh/known_hosts and ~.ssh/known_hosts - list of public keys for all the hosts to which the user has connected with ssh. for verifying the identity of client's systems. protecting against impersonation or man-in-the-middle attacks.
  • ~/.ssh/authorized_keys - mandatory, not added automatically
• /etc/ssh/ssh_config - client conf
  • ~/.ssh/config

• 0600 ~/.ssh/authorized_keys # rw
• 0600 ~/.ssh/known_hosts
• 0644 ~/.ssh/config # rw-r-r
• 0600 ~/.ssh/id_rsa # rw
• 0644 ~/.ssh/id_rsa.pub # rw-r-r
• 0700 or 755 /ssh
• 644 /etc/ssh_config
• 600 /etc/ss_config

1. password
   • PasswordAuthentication yes
2. public key
3. Host-based - public key + ip white list
   • EnableSSHKeySign yes
   • HostbasedAuthentication yes
   • IgnoreRhosts no
4. keyboard-interactive - server sends prompts to the Client who should provide the correct response.
   • KbdInteractiveAuthentication yes
   • ChallengeResponseAuthentication yes
5. challenge-response - A specific backend system sends the challenges to the client’s PC and verifies the response.
   • ChallengeResponseAuthentication yes
   • KbdInteractiveAuthentication yes
6. GSSAPI - Kerberos authentication
   • GssapiAuthentication
   • GssapiKeyExchange

• /usr/sbin/sshd -t # validate its configuration
• ssh-add -l # list keys
• copy files
  • from remote to local
    • rsync username@ip_address:/home/username/filename .
    • scp filename username@ip_address:/home/username .
    • rsync -r source_folder/ dest_folder/ # recurse copy contents of the source folder into dest_folder
    • rsync -vP username@host:/path/to/file . # download large file with progress
  • from local to the remote
    • rsync username@ip_address:/home/username/filename .
    • scp filename username@ip_address:/home/username
• ssh -t command # execute command right after login

• scp - secure file copy
• sftp - secure file transfer
• ssh-add - add private key identities to the authentication agent
• ssh-agent - authentication agent
• ssh-copy-id - use locally available keys to authorize logins on a remote machine
• ssh-keygen - authentication key utility
• ssh-keyscan - gather SSH public keys from servers
• sshd - OpenSSH daemon

• net-misc/openssh
• Config server:
  • PasswordAuthentication yes
  • PermitRootLogin yes
  • PubkeyAuthentication yes # allow migrate to pubkey (not required)
  • ListenAddress 0.0.0.0 # and add rc_need="net.enp" to /etc/conf.d/sshd (not required)
• sshd -t

client: ssh user@127.16.0.1

Just don’t use ECDSA/DSA!

1. create and copy key at client
   • ssh-keygen -b 4096 -t rsa -f ~/.ssh/mykey_rsa
   • ssh-keygen -t ed25519 -a 256 (-f ~/.ssh/id_ed25519 -C "username@hostname")
     • add -q -N "" for empty passphrase
   • ssh-copy-id -i ~/.ssh/id_rsa.pub 172.16.0.1
   • ssh user@172.16.0.1 # try loggin
   • eval `ssh-agent`
   • ssh-add home/user.ssh/id_rsa
   • ssh user@172.16.0.1 # try loggin
2. server - change config of sshd
   • PermitRootLogin no # if not needed
   • PasswordAuthentication no
   • HostbasedAuthentication no
   • KbdInteractiveAuthentication no # keyboard-interactive
   • # UsePAM yes # should be commented
   • AllowUsers user1 user2 # restrict access for this users only
   • sshd -t

1. client - samplify ~/.ssh/config
   • Host ssh-ex
     • HostName 104.236.90.57
     • User fideloper
     • IdentitiesOnly yes # where ssh-agent offers many different identities. (optional)
     • IdentityFile ~/.ssh/id_sshex
     • PreferredAuthentications publickey # (optional)

1. uncomment /etc/ssh/sshd_config: Subsystem sftp /usr…
2. for autocompletion at client: echo "net-misc/openssh libedit" >> /etc/portage/package.use/openssh

to start a graphical applications installed on a remote Linux system and forward that application windows (screen) to the local system

1. /etc/sshd_config
   • ForwardX11=yes
2. ssh -Y host

ssh -X - is not working:

• Warning: untrusted X11 forwarding setup failed: xauth key data not generated
• xset: ubable to open display ""

• File systems —> [*] FUSE (Filesystem in Userspace) support
• emerge –ask net-fs/sshfs
• umount: fusermount -u /path/to/local/sshfs/mount

Options for access:

• -o allow_other
  • replace allow_other with allow_root, for root).
• -o umask=M
  • set file permissions (octal)
• -o uid=N
  • set file owner
• -o gid=N
  • set file group

It is recommended to run SSHFS as regular user (not as root).

There is your options:

1. run as root
   • only root can access folder
   • with allow_other - you must hide folder as subfolder and set permissions on parent folder
     • chmod o-rwx /mnt
     • chown root:users /mnt
     • mkdir /mnt/share
     • sshfs -o allow_others -o uid=1000 -o gid=100 target:/mnt/share /mnt/share
2. run as user
   • only user can access folder
   • root and user can access folder but user can allow access to anyone
     • with /etc/fuse.conf uncomment: user_allow_other
     • sudo -u user sshfs -o allow_root -o uid=1000 -o gid=100 target:/mnt/share /mnt/share

/etc/fstab:

• as root (allow_other):
  • sshfs#SERVER_USER@remotehost:/SOURCEDIR home/USER/Music fuse user,_netdev,idmap=user,transform_symlinks,identityfile=/home/USER.ssh/id_rsa,allow_other,default_permissions,uid=1000,gid=1000 0 0
  • user@host:/remote/path local/path fuse.sshfs noauto,x-systemd.automount,_netdev,users,idmap=user,IdentityFile=/home/user.ssh/id_rsa,allow_other,reconnect 0 0
    • noauto tells it not to mount at boot
    • x-systemd.automount does the on-demand magic
    • _netdev tells it that it is a network device, not a block device (without it "No such device" errors might happen)
• as user:
  • user@host:/remote/path local/path fuse.sshfs noauto,x-systemd.automount,_netdev,user,idmap=user,follow_symlinks,identityfile=/home/user.ssh/id_rsa,allow_other,default_permissions,uid=USER_ID_N,gid=USER_GID_N 0 0

up:

• sshfs -o allow_other -o uid=1000 -o gid=100 target:/mnt/share /mnt/share

down:

• chmod -R g+rwx /mnt/share/* # allow at target to write
• fusermount -u /mnt/share # umount

Viriant 1 - tun - man ssh

• https://www.copahost.com/blog/openvpn-in-ubuntu-tun-tap/
• # cat /dev/net/tun
  • cat: /dev/net/tun: File descriptor in bad state
  • If the output shows “File descriptor in bad state”, then it means it is working correctly.

Variant 2 - proxychains

• ssh -fNTD 127.0.0.1:<local port> username@sshserver
  • -f go backgroound
  • -N Do not execute a remote command. This is useful for just for warding ports.
  • -T Disable pseudo-terminal allocation.
• edit /etc/proxychains.conf :
  • socks5 127.0.0.1 <localport>
  • proxy_dns
• proxychains <program name>

Variant 2 - tsocks

• net-proxy/dnsproxy
• https://github.com/awaw/dnsproxy
• test dnsproxy: dig @127.0.0.1 -p 53000 google.com (dnsutils)

problems: resolv.conf require 53 UDP port

1. you need to root to redirect to 53 port
2. UDP is not forwarded with SSH directly

solution:

• sudo -u ssh ssh -L 6667:0.0.0.0:6667 -C -o ProxyCommand='nc -X 5 -x 127.0.0.1:1082 %h %p' -p 9067 root@remove_ssh
• remote:
  • mkfifo /tmp/fifo
  • nc -l -p 6667 < /tmp/fifo | nc -u localhost 53000 > /tmp/fifo
• local:
  • socat udp-listen:53,reuseaddr,fork TCP:127.0.0.1:6667 &
  • (other) # mkfifo /tmp/fifo ; sudo nc -l -u -p 53 < /tmp/fifo | nc localhost 6667 > /tmp/fifo

• server:

  • ssh -L 6667:0.0.0:6667 root@remove_ssh (sudo -u ssh ssh -L 6667:0.0.0.0:6667 -C -o ProxyCommand='nc -X 5

  -x 127.0.0.1:1082 %h %p' -p 22 root@remove_ssh)

  • socat tcp4-listen:6667,reuseaddr,fork UDP:127.0.0.1:53000
• local:
  • socat udp-listen:53,reuseaddr,fork TCP:127.0.0.1:6667 &
  • (bad)# mkfifo /tmp/fifo ; sudo nc -l -u -p 53 < /tmp/fifo | nc localhost 6667 > /tmp/fifo
  • /etc/resolv.conf: nameserver 127.0.0.1
  • prevent dhcpd overweite /etc/resolv.conf: chattr +i /etc/resolv.conf

/tmp/fifo

https://superuser.com/questions/53103/udp-traffic-through-ssh-tunnel

• key manager for SSH. It holds your keys and certificates in memory, unencrypted, and ready for use by ssh
• runs in the background on your system

do not type password all the time

• eval $(ssh-agent) or eval `ssh-agent` # to start agent
• ssh-agent -k # to kill agent
• ssh-add -l # list private keys currently accessible to the agent ~/.ssh/id_rsa
• ssh-add key
• ssh-add -D - del -l list

ssh-add without any parameters - it will scan your home directory for some standard keys and add them to your agent

ssh-agent -k # kill daemon

security risk: anyone with root access on the remote host can discreetly access your local SSH agent through the socket. They can use your keys to impersonate you on other machines on the network.

How to reduce your risk when agent forwarding:

• ssh -A turns on agent forwarding for a single session.
• ssh-add -x locks the agent with a password, and ssh-add -X unlocks it
• alternative SSH agent that prompts you when it’s being used.
• ProxyJump directive: ssh -J bastion.example.com cloud.computer.internal # to connect to cloud.computer.internal via your bastion.example.com
  1. your SSH client uses keys from your agent to connect to bastion.example.com.
  2. Once connected, SSHD on the bastion connects to cloud.computer.internal and hands that connection off to your local SSH client.
  3. Your local SSH client runs through the handshake again, this time with cloud.computer.internal.
• Older versions of SSH and SSHD (prior to 7.2, released in 2016) don’t support ProxyJump:
  • ssh -o ProxyCommand="ssh bastion.example.com nc %h %p" cloud.computer.internal

https://smallstep.com/blog/ssh-agent-explained/

ssh-copy-id user@hostname.example.com -p <port-number>

copies the public key of your default identity (use -i identity_file for other identities) to the remote host.

• The client presents a public key to the server.
• The server generates and sends a brief, random message, asking the client to sign it using the private key.
• The client asks the SSH agent to sign the message and forwards the result back to the server.
• The server checks the signature using the client’s public key.
• The server now has proof that the client is in possession of their private key.
• Later in the handshake process, a set of new, ephemeral and symmetric keys are generated and used to encrypt the SSH session traffic. These keys may not even last the entire session; a “rekey” event happens at regular intervals.

В начале - настраиваем сервар на аутентификация по ключу

1. на клиенте (без пароля): ssh-keygen -o -b 4096 -t rsa -f ~/.ssh/mykey_rsa
2. на сервере по рутом /etc/ssh/sshd_config:
   • PermitRootLogin yes
   • PubkeyAuthentication no
   • PasswordAuthentication yes

На клиенте - копируем публичный ключ на сервер в authorized_keys:

• ip = 10.0.0.1 - сервера
• scp user@$ip:"~/.ssh/mykey_rsa.pub" ~/.ssh/authorized_keys

потом на сервере :

• PubkeyAuthentication yes
• AuthorizedKeysFile .ssh/authorized_keys
• PasswordAuthentication no
• UsePAM no - Also verify UsePAM yes is not in the configuration file; it overrides the public key authentication mechanism. Alternatively PasswordAuthentication or ChallengeResponseAuthentication directives can be disabled

X: конектится по ssh сразу под тем пользователем под которым хочешь запустить X-приложение

• /etc/ssh/sshd_config
  • X11Forwarding yes
  • X11DisplayOffset 10

wine msiexec /i E82.40_CheckPointVPN.msi

SOCKS 5 прокси ssh -D 8888 user@33.224.56.34

restict one command with argument

1. command="./nuke $SSH_ORIGINAL_COMMAND",no-port-forwarding,no-x11-forwarding,no-agent-forwarding KEY_TYPE KEY COMMENT
2. ./nuke:
   • set -euf -o pipefail
   • echo "$@"

copy public key to remote machine

• ssh-copy-id -i ~/.ssh/id_rsa.pub 192.168.0.1

IdentityFile - replace for "ssh -i"

# alias:
Host github.com
    HostName github.com
    Port 22
    User git_username
    IdentityFile ~/.ssh/rsa_id
    PreferredAuthentications publickey

• RSA - difficulty of factoring large numbers
• DSA - no longer recommended.
• ECDSA - weak - elliptic curves. Only three key sizes are supported: 256, 384, and 521 (sic!) bits.

• ed25519 (EdDS) - new

  https://stribika.github.io/2015/01/04/secure-secure-shell.html

• Protocol 2 #Protocol 1 is fundamentally broken
• StrictModes yes #Protects from misconfiguration

Diffie-Hellman key exchange

• use 2048-bit or larger primes

RFC4419: The use of multiple moduli inhibits a determined attacker from precalculating moduli exchange values, and discourages dedication of resources for analysis of any particular modulus.

generate new non elliptic-curve primes do this:

• ssh-keygen -G moduli-2048.candidates -b 2048
• ssh-keygen -T moduli-2048 -f moduli-2048.candidates
• cp moduli-2048 /etc/ssh/moduli

soft

• sshguard
• fail2ban
• Logjam Attack https://weakdh.org/

Stronger sshd_config:

• ClientAliveInterval 60 # seconds

https://www.techrepublic.com/article/how-to-use-local-and-remote-ssh-port-forwarding/

-N - Do not execute a remote command. This is useful for just forwarding ports. -f - background

Require: GatewayPorts yes in sshd_config ???

target:

• ssh -fN -R 7010:localhost:23 username@yourMachine
• yourMachine:7010 will be forwarded to target:22

https://jfrog.com/connect/post/reverse-ssh-tunneling-from-start-to-end/ https://www.marksanborn.net/howto/bypass-firewall-and-nat-with-reverse-ssh-tunnel/

compare private and public

• diff <( ssh-keygen -y -e -f "id_rsa" ) <( ssh-keygen -y -e -f "id_rsa.pub" )

login to directory

ssh root@host -t "cd /directory_wanted ; bash --login"

1. /etc/ssh/sshd_config

  Match Group sftp_users
  X11Forwarding no
  AllowTcpForwarding no
  ChrootDirectory /ubuntu # user folder
  ForceCommand internal-sftp

1. /etc/passwd:
   • ubuntu:x:1001:1001::/ubuntu:
2. folder
   • mkdir /ubuntu
   • chown root.root ubuntu

• Памятка пользователям ssh https://habr.com/en/post/122445/
• https://en.wikibooks.org/wiki/OpenSSH/Cookbook/Public_Key_Authentication
• https://help.ubuntu.com/community/SSH/OpenSSH/Configuring
• config example https://stosb.com/blog/explaining-my-configs-sshd_config/

• required: net-analyzer/openbsd-netcat
• ssh -o ProxyCommand='nc -X 5 -x 127.0.0.1:1081 %h %p' root@host

Connection closed by UNKNOWN port 65535

• error in ProxyCommand

• apt update
• apt install tor
• server /etc/tor/torrc:

ShutdownWaitLength 1 seconds
# ExcludeNodes {ru}, {cn}, {by}, {kz}, {sy}, {am}, {in} # paranoid
GeoIPExcludeUnknown 1 # paranoid
Sandbox 0 # not compatible with obfs4
Log notice file /var/log/tor/tor_notices.log
SocksPort 0
ExitRelay 0
BridgeRelay 0
HiddenServiceDir /var/lib/tor/ssh
HiddenServicePort 22 127.0.0.1:22

Steps:

1. Client:

openssl genpkey -algorithm x25519 -out key.private.pem
cat key.private.pem | grep -v " PRIVATE KEY" | base64 -d | tail --bytes=32 | base32 | sed 's/=//g' > private.key
openssl pkey -in key.private.pem -pubout | grep -v " PUBLIC KEY" | base64 -d | tail --bytes=32 | base32 | sed 's/=//g' > public.key
echo KEY_PUB=$(cat public.key)

1. Server:
2. <HiddenServiceDir>/authorized_clients/<user>.auth
   • descriptor:x25519:<public.key>
3. mkdir /var/lib/tor/ssh
4. chmod go-a var/lib tor/ssh
5. Client:
6. torrc: ClientOnionAuthDir /var/lib/tor/userauth
7. create file: <ClientOnionAuthDir>/<user>.auth_private
   • <56-char-onion-addr-without-.onion-part>:descriptor:x25519:<private.key>

KEY_USER=ta
ONION=xfe4swdndyhauaxj5di5ewnce2egr7qonn475vvopywonpe76jara2id.onion
PRIVATE=
cat <<EOF > userauth.sh
#!/bin/bash
echo "${ONION:0:56}:descriptor:x25519:$PRIVATE" > /var/lib/tor/userauth/$KEY_USER.auth_private
EOF

SSH_TOR_PORT=88
SSH_PORT=49382
KEY_USER=ta
KEY_PUB=P66JHL7W3R32O2DJBSGNVNR66JKJAS4KDG5Q4Q4EQM7CVH3X3IGQ
apt update
apt install tor
cat <<EOF > /etc/tor/torrc
RunAsDaemon 1
ShutdownWaitLength 1 seconds
GeoIPExcludeUnknown 0
Sandbox 0 # not compatible with obfs4
Log notice file /var/log/tor/tor_notices.log
SocksPort 0
ExitRelay 0
BridgeRelay 0
HiddenServiceDir /var/lib/tor/ssh
HiddenServicePort $SSH_TOR_PORT 127.0.0.1:$SSH_PORT
EOF
mkdir -p /var/lib/tor/ssh/authorized_clients
chmod -R 700 /var/lib/tor/ssh
chown -R debian-tor:debian-tor /var/lib/tor/ssh
echo "descriptor:x25519:$KEY_PUB" > /var/lib/tor/ssh/authorized_clients/$KEY_USER.auth
systemctl restart tor
sleep 7
cat /var/lib/tor/ssh/hostname

https://www.maths.tcd.ie/~fionn/misc/ssh_hidden_service/

Copy from remote to local

• rsync required on remote host:

rsync -avzhP -e "ssh -p 6767" root@41.80.200.1:/home/rtorrent/downloads/Guns* /home/ssh/downloads/

By default, jq pretty-prints JSON output.

• –raw-output / -r raw JSON or string without quotes
• –raw-output0 new lines replace with NUL
• –compact-output / -c:
• –color-output / -C and –monochrome-output / -M:
• –indent n
• –tab - use tab instead of spaces

• .[] get element
• ".[] | .name" access field
• " | .name" map for every
• "map(.name)" map for every
• "| keys" function: get the keys of an object
• "| length" function: get length
• map(has("name")) check key exist and return true or false
• min/max
• unique
• jq '.[] | select(.color=="yellow")' - by condition
• .[] | select(.name|test("^o.")) - by regex match

omit one of the indexes:

echo '[1,2,3,4,5,6,7,8,9,10]' | jq '.[:6]' | jq '.[-2:]' # [ 5, 6 ]

echo '{"fruit1":{"name":"apple"},"fruit2":{"name":"orange"}}' | jq '.[] | select(.name|test("^o."))'

echo '{"fruit":{"name":"apple","color":"green","price":1.20}}' | jq -r 'map(has("name"))'

[
  true
]

{
  "result": {
    "alternatives": [
      {
        "message": {
          "role": "assistant",
          "text": "Согласно документации"
        },
        "status": "ALTERNATIVE_STATUS_FINAL"
      }
    ],
    "usage": {
      "inputTextTokens": "29",
      "completionTokens": "77",
      "totalTokens": "106"
    },
    "modelVersion": "18.01.2024"
  }
}

cat | jq "map(.alternatives)"

• —null-input / -n

BUCKET_NAME=testbucket
OBJECT_NAME=testworkflow-2.0.1.jar
TARGET_LOCATION=/opt/test/testworkflow-2.0.1.jar

jq -n \
   --arg bn "$BUCKET_NAME" \
   --arg on "$OBJECT_NAME" \
   --arg tl "$TARGET_LOCATION" \
   '{bucketname: $bn, objectname: $on, targetlocation: $tl}'