util

[!NOTE|label:references:]
Hidden features of Bash

system command

use parameter in `xargs`

$ find . -type f | xargs -n 1 -I FILE bash -c 'echo $(file --mime-type -b FILE)'
text/plain
text/plain
text/plain
inode/x-empty
text/plain
text/plain
text/plain
text/plain
text/plain
text/plain

find commands belongs to and come from

belongs to

$ type which
which is aliased to `alias | which -a --tty-only --read-alias --show-dot --show-tilde'

$ type bello
bello is a function
bello ()
{
  source "${iRCHOME}/.imac"
}

come from

$ shopt -s extdebug

$ declare -F _completion_loader
_completion_loader 2219 /usr/local/Cellar/bash-completion@2/2.11/share/bash-completion/bash_completion

$ declare -F _docker
_docker 5463 /usr/local/etc/bash_completion.d/docker

$ declare -F __git_ps1
__git_ps1 340 /usr/local/etc/bash_completion.d/git-prompt.sh

$ declare -F bello
bello 79 /Users/marslo/.marslo/.marslorc

linux

$ bash --debugger
$ declare -F _docker
_docker 5011 /usr/share/bash-completion/completions/docker

find alias come from

[!NOTE|label:references:]
Is it possible to check where an alias was defined?

$ bash -ixlc : 2>&1 | grep ...
$ zsh -ixc : 2>&1 | grep ...

i.e.:

$ bash -ixlc : 2>&1 | grep 'clr='
    /Users/marslo/.marslo/.alias/docker::16: alias 'dclr=docker system prune -a -f'
    /Users/marslo/.marslo/.alias/utils::22: alias clr=clear

get command from PATH

[!NOTE|label:references:]
How to use which on an aliased command?

$ type -a kubectl
kubectl is aliased to `kubecolor'
kubectl is /Users/marslo/.docker/bin/kubectl

type -P

$ type -P kubectl
/Users/marslo/.docker/bin/kubectl

/usr/bin/which

$ /usr/bin/which kubectl
/Users/marslo/.docker/bin/kubectl

which --skip-alias

$ which --skip-alias kubectl
~/.docker/bin/kubectl

shopt -u expand_aliases

$ type -a kubectl
kubectl is aliased to `kubecolor'
kubectl is /Users/marslo/.docker/bin/kubectl

$ shopt -u expand_aliases
$ type -a kubectl
kubectl is /Users/marslo/.docker/bin/kubectl

$ shopt -s expand_aliases

check alias only

$ echo ${BASH_ALIASES[kubectl]}
kubecolor

get all google website

$ whois www.google.com

Whois Server Version 2.0

Domain names in the .com and .net domains can now be registered
with many different competing registrars. Go to http://www.internic.net
for detailed information.

  Server Name: WWW.GOOGLE.COM.VN
  Registrar: ENOM, INC.
  Whois Server: whois.enom.com
  Referral URL: http://www.enom.com

  Server Name: WWW.GOOGLE.COM.TW
  Registrar: ENOM, INC.
  Whois Server: whois.enom.com
  Referral URL: http://www.enom.com

  Server Name: WWW.GOOGLE.COM.TR
  Registrar: TUCOWS DOMAINS INC.
  Whois Server: whois.tucows.com
  Referral URL: http://domainhelp.opensrs.net

  Server Name: WWW.GOOGLE.COM.SA
  Registrar: OMNIS NETWORK, LLC
  Whois Server: whois.omnis.com
  Referral URL: http://domains.omnis.com

  Server Name: WWW.GOOGLE.COM.PK
  Registrar: INTERNET.BS CORP.
  Whois Server: whois.internet.bs
  Referral URL: http://www.internet.bs

  Server Name: WWW.GOOGLE.COM.PE
  Registrar: HOSTOPIA.COM INC. D/B/A APLUS.NET
  Whois Server: whois.names4ever.com
  Referral URL: http://www.aplus.net

  Server Name: WWW.GOOGLE.COM.MX
  Registrar: ENOM, INC.
  Whois Server: whois.enom.com
  Referral URL: http://www.enom.com

  Server Name: WWW.GOOGLE.COM.HK
  Registrar: GKG.NET, INC.
  Whois Server: whois.gkg.net
  Referral URL: http://www.gkg.net

  Server Name: WWW.GOOGLE.COM.DO
  Registrar: ENOM, INC.
  Whois Server: whois.enom.com
  Referral URL: http://www.enom.com

  Server Name: WWW.GOOGLE.COM.CO
  Registrar: ENOM, INC.
  Whois Server: whois.enom.com
  Referral URL: http://www.enom.com

  Server Name: WWW.GOOGLE.COM.BR
  Registrar: ENOM, INC.
  Whois Server: whois.enom.com
  Referral URL: http://www.enom.com

  Server Name: WWW.GOOGLE.COM.AU
  Registrar: MELBOURNE IT, LTD. D/B/A INTERNET NAMES WORLDWIDE
  Whois Server: whois.melbourneit.com
  Referral URL: http://www.melbourneit.com

  Server Name: WWW.GOOGLE.COM.AR
  Registrar: ENOM, INC.
  Whois Server: whois.enom.com
  Referral URL: http://www.enom.com

>>> Last update of whois database: Mon, 24 Feb 2014 17:24:05 UTC <<<

perm

[!NOTE|label:references:]
backup and restore filer & folder permission

backup

$ find . -printf '%m\t%u\t%g\t%p\0' > file.perm

restore

while read -rd $'\0' perms user group file; do
  if [ -e "$file" ]; then
    chown "$user:$group" "$file"
    chmod "$perms" "$file"
  else
    echo "warning: $file not found"
  fi
done < file.perm

check perm

find & printf

$ find $PWD -printf '%m\t%u\t%g\t%p\n' | head
755 marslo  staff /Users/marslo
755 marslo  staff /Users/marslo/.eclipse
755 marslo  staff /Users/marslo/.eclipse/org.eclipse.oomph.jreinfo
644 marslo  staff /Users/marslo/.eclipse/org.eclipse.oomph.jreinfo/defaults.properties
644 marslo  staff /Users/marslo/.eclipse/org.eclipse.oomph.jreinfo/infos.txt

$ find $PWD -printf '%M %u %g %p\n' | head
drwxr-xr-x marslo staff /Users/marslo
drwxr-xr-x marslo staff /Users/marslo/.eclipse
drwxr-xr-x marslo staff /Users/marslo/.eclipse/org.eclipse.oomph.jreinfo
-rw-r--r-- marslo staff /Users/marslo/.eclipse/org.eclipse.oomph.jreinfo/defaults.properties

stat

$ stat -c '%A %a %n' *
drwx------ 700 Applications
drwx------ 700 Desktop
drwx------ 700 Documents
drwx------ 700 Downloads
drwx------ 700 Library
drwx------ 700 Movies
drwx------ 700 Music
drwx------ 700 Pictures
drwxr-xr-x 755 Public
drwxr-xr-x 755 mywork
drwxr-xr-x 755 test

namei

$ namei -l $PWD
/Users/marslo
  / = drwxr-xr-x l=22 u=root/0 g=admin/80 s=704 m=07-16-2020@13:40:21
  Users = drwxr-xr-x l=6 u=root/0 g=admin/80 s=192 m=09-30-2019@04:22:36
  marslo = drwxr-xr-x l=72 u=marslo/501 g=staff/20 s=2304 m=07-16-2020@17:37:27

gpg

encrypt bash file

$ echo "ls" > script.bash; gpg -c script.bash; cat script.bash.gpg | gpg -d --no-mdc-warning | bash

install apt keys

[!TIP]
* iMarslo : keyring
step by step by apt-key add
Hockeypuck OpenPGP keyserver

via gpg

$ gpg --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF

more options

$ gpg --ignore-time-conflict \
      --no-options \
      --no-default-keyring \
      --homedir /tmp/tmp.Hrb5ETPac2 \
      --no-auto-check-trustdb \
      --trust-model always \
      --keyring /etc/apt/trusted.gpg \
      --primary-keyring /etc/apt/trusted.gpg \
      --keyserver keyserver.ubuntu.com \
      --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF

via apt-key adv

$ apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF

via apt-key add

$ curl -sL "http://keyserver.ubuntu.com/pks/lookup?op=get&search=0xA6A19B38D3D831EF" | sudo apt-key add

Ghostbird/add-repository

$ ./add-repository "https://keyserver.ubuntu.com/pks/lookup?search=0x3fa7e0328081bff6a14da29aa6a19b38d3d831ef&op=get" "deb https://download.mono-project.com/repo/debian stable-buster main" mono-official-stable.list

others

# dockerfile
RUN apt install -y gnupg ca-certificates
RUN gpg --keyserver keyserver.ubuntu.com --recv 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
RUN gpg --export 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF | tee /usr/share/keyrings/mono.gpg >/dev/null
RUN gpg --batch --yes --delete-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
RUN echo "deb [signed-by=/usr/share/keyrings/mono.gpg] https://download.mono-project.com/repo/debian stable-buster main" | tee /etc/apt/sources.list.d/mono-official-stable.list
RUN apt update
RUN apt install -y mono-devel

inode

get inode of a file

$ l -i a_b
10224132 -rw-r--r-- 1 marslo marslo 10 Feb 21 00:43 a_b

get inodes in a folder

stat

$ stat -c '%i' ~
686476

equivalent to
```
$ ls -id ~
686476 /Users/marslo
```

example

$ ls -id  /local_storage/docker
2818591238 /local_storage/docker

ls

$ ls /local_storage/docker -AiR1U |
     sed -rn '/^[./]/{h;n;};G;
         s|^ *([0-9][0-9]*)[^0-9][^/]*([~./].*):|\1:\2|p' |
     sort -t : -uk1.1,1n |
     cut -d: -f2 | sort -V |
     uniq -c | sort -rn | head -n10
     46 /Users/marslo/test/keepalived-2.0.18/lib
     29 /Users/marslo/test
     28 /Users/marslo/test/keepalived-2.0.18/doc/samples
     27 /Users/marslo/test/jenkins/vars
     23 /Users/marslo/test/keepalived-2.0.18
     22 /Users/marslo/test/keepalived-2.0.18/doc/source
     17 /Users/marslo/test/jenkins/jenkinsfile
     16 /Users/marslo/test/autosquash/.git/objects
     14 /Users/marslo/test/keepalived-2.0.18/keepalived/vrrp
     14 /Users/marslo/test/jenkins/configs/etc/yum.repos.d

df

 $ df -i
Filesystem                            Type   Inodes IUsed IFree IUse% Mounted on
/dev/disk1s5s1                        apfs     2.3G  555K  2.3G    1% /
/dev/disk1s4                          apfs     2.3G     2  2.3G    1% /System/Volumes/VM
/dev/disk1s2                          apfs     2.3G  1.2K  2.3G    1% /System/Volumes/Preboot
/dev/disk1s6                          apfs     2.3G    16  2.3G    1% /System/Volumes/Update
/Library/Input Methods/SogouInput.app nullfs   2.3G  1.8M  2.3G    1% /private/var/folders/s3/mg_f3cv54nn7y758j_t46zt40000gn/T/AppTranslocation/1E49F6C4-251F-443B-8D8A-86DA8F531F09

du

$ sudo du --inodes -S ~ \
       | sort -rh \
       | sed -n '1,50{/^.\{71\}/s/^\(.\{30\}\).*\(.\{37\}\)$/\1...\2/;p}' \
       | head -10
14994 /Users/marslo/Library/Co...icrosoft User Data/OneNote/15.0/cache
13453 /Users/marslo/Library/Gr...s/Main Profile/Files/S0/1/Attachments
4667  /Users/marslo/Library/Caches/Google/Chrome Canary/Default/Cache
4086  /Users/marslo/Library/Gro...ofiles/Company/Files/S0/1/Attachments
3912  /Users/marslo/Library/Con...476b0cb6d7b78ea9f492c743c1bdfa/Avatar
3359  /Users/marslo/Library/Con...6d7b78ea9f492c743c1bdfa/Stickers/File
3174  /Users/marslo/Library/App...versions/3.8.6/openssl/share/man/man3
3174  /Users/marslo/Library/App...6/openssl/share/doc/openssl/html/man3
3174  /Users/marslo/Library/App...versions/3.7.9/openssl/share/man/man3
3174  /Users/marslo/Library/App...9/openssl/share/doc/openssl/html/man3

check inode status

$ sudo tune2fs -l /dev/sdb1 | grep inode
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Free inodes:              234152632
First inode:              11
Journal inode:            8
First orphan inode:       44171696
Journal backup:           inode blocks

extend inode

reference:
Modifying the inode count for an ext2/ext3/ext4 file system
RHEL: Extending the maximum inode count on a ext2/ext3/ext4 filesystem

check linux window size

check

$ shopt | grep checkwinsize
checkwinsize    on

enable
```
$ shopt -s checkwinsize
```

readline & bind

[!NOTE]
8.4.6 Letting Readline Type For You

get info

get current keymap

$ bind -v | awk '/keymap/ {print $NF}'
vi-insert

tricky for switch keymap

set keymap emacs
"\ee": vi-editing-mode

set keymap vi-insert
"\e": vi-movement-mode

set keymap vi-command
"\ee": emacs-editing-mode

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