[!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/Marvell/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

util

system command

use parameter in `xargs`

find commands belongs to and come from

find alias come from

get command from PATH

get all google website

perm

backup

restore

check perm

gpg

encrypt bash file

install apt keys

inode

get inode of a file

get inodes in a folder

check inode status

extend inode

check linux window size

readline & bind

get info

results matching ""

No results matching ""

system command

use parameter in xargs

find commands belongs to and come from

find alias come from

get command from PATH

get all google website

perm

backup

restore

check perm

gpg

encrypt bash file

install apt keys

inode

get inode of a file

get inodes in a folder

check inode status

extend inode

check linux window size

readline & bind

get info

results matching ""

No results matching ""

use parameter in `xargs`