Note_Tech

All technological notes.

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Linux - File System: File Operation

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• Linux - File System: File Operation
  • Create new file
  • List files
    • ls: List Files
    • tree: list in tree
  • Search files and directories
    • locate: find files using index
    • find: advanced search
      • Commands
    • Lab: Find
  • Move, Copy, Delete
  • Archive/Compress Files
    • Archive commands
    • Lab: Archive
      • Create archive file without Compression
      • Extract archived files
      • Create archive file with Compression
      • Archive multiple files
      • Append file to existing tarfile
      • Restore a specific file from tarfile
    • Compress Commands
    • Lab: Compress File with gzip
    • Lab: Compress File with bzip2
  • File’s Disk Usage

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Create new file

Cmd	desc
touch file	create new file
touch -d 2019-09-20 file	Set the date on file1
touch -m file	change the modification time
cp file destinatio	copy and create new file
vi file	Create new file using vi editor

• vi:
  • file would be created unless saving the file.

touch newfile
ll
# total 0
# -rw-r--r--. 1 root root 0 Feb 12 13:41 newfile

# Change date on a file
touch -d 2019-02-09 newfile
# confirm
ll
# total 0
# -rw-r--r--. 1 root root 0 Feb  9  2019 newfile

# Change modfication time
touch -m newfile
ll
# total 0
# -rw-r--r--. 1 root root 0 Feb 12 13:42 newfile

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List files

ls: List Files

Command	Desc
ls	List files and direcotry
ls -alht	List files and direcotry
ls -F	lists the contents and appends symbols to indicate file types.
ls -t	lists files sored by time, most recent file placed at the top
ls -r	lists file wit reverse order.
ls -R	lists file recursively
ls -d	lists directory name, not contents
ls --color	Colorize the output

• ls -F

  • indicator appended:
    • /: Directory
    • @: Link
    • *: Executable

• ls -p | grep -v /:

  • List files only

• ls -lt

  • list files base on time
    • newest: at the top
    • oldest: at the bottom

• ls -ltr

  • list files base on time reversely
    • newest: at the bottom
    • oldest: at the top

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tree: list in tree

• tree:
  • list contents of directories in a tree-like format

Commande	Desc
tree -d	List directories only
tree -C	Colosize output

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Search files and directories

locate: find files using index

• locate pattern:
  • find files by name
  • pattern is requried
  • locate if faster than find
    • queries an index
    • result are not in real time,非实时，与 index 的失效有关。
      • 新建的文件可能未被 index， 所以无法被 locate
    • 如需要实时，则使用 find

Command	Desc
locate pattern	Find files and directories matching the pattern
locate uptime	matching the pattern
locate upti	matching the pattern
updatedb	updated manually

locate passwd
# /etc/passwd
# /etc/passwd-
# /etc/pam.d/passwd
# /etc/security/opasswd
# /usr/bin/gpasswd
# /usr/bin/grub2-mkpasswd-pbkdf2
# /usr/bin/passwd
# /usr/lib/firewalld/services/kpasswd.xml
# /usr/lib64/samba/pdb/smbpasswd.so
# /usr/lib64/security/pam_unix_passwd.so
# /usr/sbin/chgpasswd
# /usr/sbin/chpasswd
# /usr/sbin/lpasswd
# ...

# limit return
locate -n 3 passwd
# /etc/passwd
# /etc/passwd-
# /etc/pam.d/passwd

locate .sh -n2
# /etc/X11/xinit/xinitrc.d/50-systemd-user.sh
# /etc/X11/xinit/xinitrc.d/localuser.sh

locate -S
# Database /var/lib/mlocate/mlocate.db:
#         10,323 directories
#         134,075 files
#         6,859,661 bytes in file names
#         3,264,303 bytes used to store database

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find: advanced search

• find:

  • search for files in a directory hierarchy
  • find files match the expression
  • default: find all files in the current directory

• Syntax:

  • find + path + search option + action

• search option

  • by name: -name / -iname
  • by UID//GID: -user / -group
  • by permissions: -perm
  • by inode: -inum
  • by access time: -atime / -amin
  • by modification time: -mtime / -amin
  • by size / type: -size / -type

• Action

  • -exec cmd {} \
  • -ok cmd {} \
  • -delete

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Commands

• Find by file attributes

Command	Desc
find	Find everything under the current directory
find /etc -name "*Text"	Find the file that ends with “Text”
find /etc -iname "Text"	ignore case
find /etc -iname "Text" -ls	Performs ls on each of the found items
find /usr -size +1M	Finds file that are larger than 1M
find /usr -size -1M	Finds file that are smaller than 1M
find /var -user rheladmin	Finds file owned by a user
find /var -group rheladmin	Finds file owned by a group
find /etc -user root -not -group root	Finds file owned by a user by not by a group
find /root -maxdepth 2 -type d	Finds directory with max 2 depth
find /root -mindepth 2 -maxdepth 3 -type d	Finds directory with min 2 depth and max 3 depth
find /dev -perm 660	Finds file with permission
find /dev -perm -222	Finds file with at least (-222) writable permissions
find /usr -type l -perm -ug=rw	Finds link with read and write for user and group

• Find by time

Command	Desc
find /etc -mtime 0	Finds fine modified today
find /etc -mtime 1	Finds fine modified yesterday
find /etc -mtime +3000	Finds fine modified more than 3000 days
find /var/log -mmin -30	Finds file modified less than 30 min
find /usr -mtime +10 -mtime -90	Finds files that are more 10 days old but less than 90 days old
find -newer /root/sdir/	Finds file that are newer than file.
find /etc -type d -newer /etc/passwd	Find all directories that are newer than the passwd file

• Exec/ok
  • -ok: need confirm
  • {}: replace the found items
  • \;: escape ; which terminate the command

Command	Desc
find / -name core -type d -exec ls -ld {} \;	List all found directory
find . -exec file {} \;	Execute file command on each items under the current directory
find /etc/sysconfig -name *.conf -ok cp {} /tmp \;	Copies each file or directory recursively to the path
find /home -user rheladmin -exec cp -r --parents {} /tmp \;	Copies each file or directory recursively to the path

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Lab: Find

# case sensitive
find /etc -name "*Text"
# /etc/brltty/Text

# case insensitive
find /etc -iname "*Text"
# /etc/selinux/targeted/contexts/initrc_context
# /etc/selinux/targeted/contexts/removable_context
# /etc/selinux/targeted/contexts/userhelper_context
# /etc/selinux/targeted/contexts/virtual_domain_context
# /etc/selinux/targeted/contexts/virtual_image_context
# /etc/selinux/targeted/contexts/failsafe_context
# /etc/brltty/Text

# list
find /etc -name "*Text" -ls
#  880503      8 drwxr-xr-x   2 root     root         4096 Jan 27 02:26 /etc/brltty/Text
find /etc -iname "*Text" -ls
#  938234      4 -rw-r--r--   1 root     root           30 Jan 11  2024 /etc/selinux/targeted/contexts/initrc_context
#  938237      4 -rw-r--r--   1 root     root           33 Jan 11  2024 /etc/selinux/targeted/contexts/removable_context
#  938306      4 -rw-r--r--   1 root     root           33 Jan 11  2024 /etc/selinux/targeted/contexts/userhelper_context
#  938307      4 -rw-r--r--   1 root     root           62 Jan 11  2024 /etc/selinux/targeted/contexts/virtual_domain_context
#  938308      4 -rw-r--r--   1 root     root           71 Jan 11  2024 /etc/selinux/targeted/contexts/virtual_image_context
# 2172386      4 -rw-r--r--   1 root     root           29 Feb 15 13:43 /etc/selinux/targeted/contexts/failsafe_context
#  880503      8 drwxr-xr-x   2 root     root         4096 Jan 27 02:26 /etc/brltty/Text

# find by size
find /usr -size +100M
# /usr/lib/locale/locale-archive
# /usr/lib/locale/locale-archive.real
# /usr/lib64/libLLVM-16.so
# /usr/lib64/firefox/libxul.so

find /usr -size -1k


# find by ownership
find /etc -user root -not -group root
# /etc/polkit-1/localauthority
# /etc/cups
# /etc/cups/classes.conf
# /etc/cups/client.conf
# /etc/cups/cups-files.conf
# /etc/cups/cups-files.conf.default
# /etc/cups/cupsd.conf
# /etc/cups/cupsd.conf.default
# /etc/cups/lpoptions
# /etc/cups/ppd
# /etc/cups/printers.conf
# /etc/cups/snmp.conf
# /etc/cups/snmp.conf.default
# /etc/cups/ssl
# /etc/cups/subscriptions.conf.O
# /etc/cups/subscriptions.conf
# /etc/ssh/ssh_host_ed25519_key
# /etc/ssh/ssh_host_ecdsa_key
# /etc/ssh/ssh_host_rsa_key
# /etc/brlapi.key
# /etc/chrony.keys
# /etc/dnsmasq.conf
# /etc/dnsmasq.d
ll /etc/dnsmasq.d
# drwxr-xr-x. 2 root dnsmasq 6 Feb 28  2024 /etc/dnsmasq.d

# find by type and depth
find /usr/ -maxdepth 2 -type d -name src
# /usr/local/src
# /usr/src

# find  modified (-mtime) more than (the + sign) 2000 days ago
find /etc -mtime +2000

find /etc -mtime +3000
# /etc/dbus-1/system.d/org.freedesktop.RealtimeKit1.conf
# /etc/avahi/hosts
# /etc/xdg/user-dirs.conf
# /etc/xdg/user-dirs.defaults
# /etc/speech-dispatcher/clients/emacs.conf

find /var/log -mmin -30
# /var/log/wtmp
# /var/log/audit/audit.log
# /var/log/rhsm/rhsmcertd.log
# /var/log/rhsm/rhsm.log
# /var/log/cron
# /var/log/messages
# /var/log/secure

find /dev -type b -perm 660
# /dev/dm-1
# /dev/dm-0
# /dev/nvme0n1p3
# /dev/nvme0n1p2
# /dev/nvme0n1p1
# /dev/nvme0n1
find . -perm -222 -ls
#  2039722      0 lrwxrwxrwx   1 root     root           28 Feb 12 21:00 ./lndir/softdirln -> /root/lndir/softlink/softdir
#  2039723      0 lrwxrwxrwx   1 root     root           29 Feb 12 21:00 ./lndir/softfileln -> /root/lndir/softlink/softfile
# 20538447      0 -rwxrwxrwx   1 root     root            0 Feb 14 23:26 ./permdir/permfile

find /dev -perm -222 -type c
# /dev/vsock
# /dev/vhost-vsock
# /dev/vhost-net
# /dev/vfio/vfio
# /dev/net/tun
# /dev/dri/renderD128
# /dev/fuse
# /dev/ptmx
# /dev/tty
# /dev/urandom
# /dev/random
# /dev/full
# /dev/zero
# /dev/null

find /etc/sysconfig -name *.conf -ok cp {} /tmp \;
# < cp ... /etc/sysconfig/nftables.conf > ? y
ll /tmp/nftables.conf
# -rw-------. 1 root root 364 Feb 15 14:40 /tmp/nftables.conf

find . -exec file {} \;
# .: directory
# ./.ssh: directory
# ./.bash_logout: ASCII text
# ./.bash_profile: ASCII text
# ./.bashrc: ASCII text
# ./.cshrc: ASCII text
# ./.tcshrc: ASCII text
# ./anaconda-ks.cfg: ASCII text
# ./.cache: directory
# ./.viminfo: ASCII text
# ./.bash_history: ASCII text


ll /home/rheladmin/
# total 0
# drwxr-xr-x. 2 rheladmin rheladmin 6 Jan 27 02:33 Desktop
# drwxr-xr-x. 2 rheladmin rheladmin 6 Jan 27 02:33 Documents
# drwxr-xr-x. 2 rheladmin rheladmin 6 Jan 27 02:33 Downloads
# drwxr-xr-x. 2 rheladmin rheladmin 6 Jan 27 02:33 Music
# drwxr-xr-x. 2 rheladmin rheladmin 6 Jan 27 02:33 Pictures
# drwxr-xr-x. 2 rheladmin rheladmin 6 Jan 27 02:33 Public
# drwxr-xr-x. 2 rheladmin rheladmin 6 Jan 27 02:33 Templates
# drwxr-xr-x. 2 rheladmin rheladmin 6 Jan 27 02:33 Videos

# find and copy
find /home -user rheladmin -exec cp -r --parents  {} /tmp \;

# confirm
ll /tmp/home/rheladmin/
# total 0
# drwxr-xr-x. 2 root root 6 Feb 15 14:49 Desktop
# drwxr-xr-x. 2 root root 6 Feb 15 14:49 Documents
# drwxr-xr-x. 2 root root 6 Feb 15 14:49 Downloads
# drwxr-xr-x. 2 root root 6 Feb 15 14:49 Music
# drwxr-xr-x. 2 root root 6 Feb 15 14:49 Pictures
# drwxr-xr-x. 2 root root 6 Feb 15 14:49 Public
# drwxr-xr-x. 2 root root 6 Feb 15 14:49 Templates
# drwxr-xr-x. 2 root root 6 Feb 15 14:49 Videos

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Move, Copy, Delete

Command	Desc
mv source destination	Move/Rename file
mv -f source destination	Force to overwrite
mv -i source destination	Move/Rename file, prompt before overwrite
mv -u source destination	Move only when the SOURCE file is newer than the destination
cp sourcefile newfile	Copy file within the same direcotry
cp sourcefile dest_dir/	Copy file file to a destination directory
cp file1 file2 dest_dir	Copy multiple files to a destination directory
cp -r source_dir/ dest_dir/	Copy all files within a source direcotry to destination directory
cp -p sourcefile dest_dir/	Copy and preserve the attributes
cp -f source destination	Force copy file
cp -i source destination	Copy file, prompt before overwrite
cp -n source destination	do not overwrite an existing file
rm file	Remove file
rm -f file	Force to remove a file
rm -i file	prompt before every removal

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Archive/Compress Files

Archive commands

• create a single compressed archive of hundreds of files and directories.打包
• tar or star
  • preserve general file attributes such as ownership, owning group, and timestamp as well as extended attributes such as ACLs and SELinux contexts.

Command	Desc
tar -cf tar_file target	Create a tar archive from a target.
tar -cpf tar_file target	Create a tar archive from a target, Preserve file permissions
tar -cvfz tar_file target	Create a tar archive from a target, using gzip compression.
tar -cvjz tar_file target	Create a tar archive from a target, using bzip2 compression.
tar -tf tar_file	Display the table of contents (list).
tar -xf tar_file	Extract files from the archive.
tar -xvf tar_file	Extract files from the archive displaying a file list
tar -xvfj tar_file	Extract files from the archive displaying a file list using .bzip2 Compression

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Lab: Archive

Create archive file without Compression

mkdir /root/tardir
touch /root/tardir/sheet.csv /root/tardir/word.doc
ll /root/tardir
# total 0
# -rw-r--r--. 1 root root 0 Feb 11 19:57 sheet.csv
# -rw-r--r--. 1 root root 0 Feb 11 19:57 word.doc

# create an archive file from tardir directory
tar -cvf /root/archive.tar /root/tardir
# /root/tardir/
# /root/tardir/sheet.csv
# /root/tardir/word.doc
# confirm
ll -h /root/archive.tar
# -rw-r--r--. 1 root root 10K Feb 11 20:15 /root/archive.tar

# list a tar file's content
tar -tvf /root/archive.tar
# drwxr-xr-x root/root         0 2025-02-11 19:57 root/tardir/
# -rw-r--r-- root/root         0 2025-02-11 19:57 root/tardir/sheet.csv
# -rw-r--r-- root/root         0 2025-02-11 19:57 root/tardir/word.doc

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Extract archived files

# Extract files to /root/exdir
mkdir /root/exdir
tar -vxf /root/archive.tar -C /root/exdir
# root/tardir/
# root/tardir/sheet.csv
# root/tardir/word.doc

# confirm
ll -R /root/exdir
# /root/exdir:
# total 0
# drwxr-xr-x. 3 root root 20 Feb 11 20:05 root

# /root/exdir/root:
# total 0
# drwxr-xr-x. 2 root root 39 Feb 11 19:57 tardir

# /root/exdir/root/tardir:
# total 0
# -rw-r--r--. 1 root root 0 Feb 11 19:57 sheet.csv
# -rw-r--r--. 1 root root 0 Feb 11 19:57 word.doc

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Create archive file with Compression

# auto compress
tar -caf /root/archive_auto.tar /root/tardir

# use bzip2
tar -cjf /root/archive_bzip2.tar /root/tardir

# use gzip
tar -czf /root/archive_gzip.tar /root/tardir

# confirm and compare
ll -hS /root/archive.tar /root/archive_auto.tar /root/archive_bzip2.tar /root/archive_gzip.tar
# -rw-r--r--. 1 root root 10K Feb 11 20:22 /root/archive_auto.tar
# -rw-r--r--. 1 root root 10K Feb 11 20:15 /root/archive.tar
# -rw-r--r--. 1 root root 168 Feb 11 20:22 /root/archive_bzip2.tar
# -rw-r--r--. 1 root root 167 Feb 11 20:23 /root/archive_gzip.tar

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Archive multiple files

tar -cvf /root/archive_multi.tar /root/tardir/sheet.csv /root/tardir/word.doc
# tar: Removing leading `/' from member names
# /root/tardir/sheet.csv
# tar: Removing leading `/' from hard link targets
# /root/tardir/word.doc

# confirm
ll -h /root/archive_multi.tar
# -rw-r--r--. 1 root root 10K Feb 11 20:58 /root/archive_multi.tar
tar -tvf /root/archive_multi.tar
# -rw-r--r-- root/root         0 2025-02-11 19:57 root/tardir/sheet.csv
# -rw-r--r-- root/root         0 2025-02-11 19:57 root/tardir/word.doc

Append file to existing tarfile

# append
tar -rvf /root/archive_multi.tar /etc/fstab
# tar: Removing leading `/' from member names
# /etc/fstab
# tar: Removing leading `/' from hard link targets

# confirm
ll -h /root/archive_multi.tar
# -rw-r--r--. 1 root root 10K Feb 11 21:01 /root/archive_multi.tar
tar -tvf /root/archive_multi.tar
# -rw-r--r-- root/root         0 2025-02-11 19:57 root/tardir/sheet.csv
# -rw-r--r-- root/root         0 2025-02-11 19:57 root/tardir/word.doc
# -rw-r--r-- root/root       666 2025-01-27 02:21 etc/fstab

Restore a specific file from tarfile

tar -tvf /root/archive_multi.tar
# -rw-r--r-- root/root         0 2025-02-11 19:57 root/tardir/sheet.csv
# -rw-r--r-- root/root         0 2025-02-11 19:57 root/tardir/word.doc
# -rw-r--r-- root/root       666 2025-01-27 02:21 etc/fstab

# extract
tar -xvf /root/archive_multi.tar etc/fstab -C /root
# etc/fstab

# confirm
ll -h /root/etc/fstab
# -rw-r--r--. 1 root root 666 Jan 27 02:21 /root/etc/fstab/

tar -tvf /root/archive_multi.tar
# -rw-r--r-- root/root         0 2025-02-11 19:57 root/tardir/sheet.csv
# -rw-r--r-- root/root         0 2025-02-11 19:57 root/tardir/word.doc
# -rw-r--r-- root/root       666 2025-01-27 02:21 etc/fstab

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Compress Commands

• compression tools
  • gzip/gunzip
    • create a compressed file of each of the specified files
    • adds the .gz extension to each file
  • bzip2 /bunzip2
    • creates a compressed file of each of the specified files
    • adds the .bz2 extension to each file

Command	Desc
gzip filename	Compress the files into .gz file
gzip -c file1 > foo.gz	Compress to a destination
gzip -v filename	Verbose output
gzip -k filename	Keep the original file
gzip -r directory	Compress all files in a directory
gzip -9 filename	Change the compression level, from 1 to 9. Default 6
gunzip gz_file	Uncompress files.
gunzip -vk gz_file	Uncompress files and Verbose output, keep the gz file
bzip2 file_name	Compress the files into .bz2 file
bunzip2 bz2_file	Uncompress the files

---

Lab: Compress File with gzip

mkdir /root/gzipdir
touch /root/gzipdir/sheet.csv /root/gzipdir/word.doc


gzip /root/gzipdir/sheet.csv /root/gzipdir/word.doc

# confirm
ll -h /root/gzipdir/
# total 8.0K
# -rw-r--r--. 1 root root 30 Feb 11 20:39 sheet.csv.gz
# -rw-r--r--. 1 root root 29 Feb 11 20:39 word.doc.gz

# list files
gzip -l /root/gzipdir/sheet.csv.gz
#  compressed        uncompressed  ratio uncompressed_name
#          30                   0   0.0% /root/gzipdir/sheet.csv

# extract
gunzip /root/gzipdir/sheet.csv.gz /root/gzipdir/word.doc.gz
# confirm
ll -h /root/gzipdir/
# total 0
# -rw-r--r--. 1 root root 0 Feb 11 20:39 sheet.csv
# -rw-r--r--. 1 root root 0 Feb 11 20:39 word.doc

---

Lab: Compress File with bzip2

mkdir /root/bzip2
touch /root/bzip2/sheet.csv /root/bzip2/word.doc

ll -h /root/bzip2/
# total 0
# -rw-r--r--. 1 root root 0 Feb 11 20:45 sheet.csv
# -rw-r--r--. 1 root root 0 Feb 11 20:45 word.doc

# compress with bzip2
bzip2 /root/bzip2/sheet.csv /root/bzip2/word.doc
# confirm
ll -h /root/bzip2/
# total 8.0K
# -rw-r--r--. 1 root root 14 Feb 11 20:45 sheet.csv.bz2
# -rw-r--r--. 1 root root 14 Feb 11 20:45 word.doc.bz2

# extract
bunzip2  /root/bzip2/sheet.csv.bz2 /root/bzip2/word.doc.bz2
ll -h /root/bzip2/
# total 0
# -rw-r--r--. 1 root root 0 Feb 11 20:45 sheet.csv
# -rw-r--r--. 1 root root 0 Feb 11 20:45 word.doc

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File’s Disk Usage

Command	Desc
du	Estimates file usage in current path
du dir/file	Estimates file usage of a dir/file
du -k dir/file	Display sizes in Kilobytes.
du -h dir/file	Display sizes in human readable format.

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