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arvin karimi edited this page Apr 6, 2018 · 3 revisions

Table of Contents:

file and directory manipulation

general

permisions :

  • Srwxrwxrwx r = 4 w = 2 x = 1 S = sticky bit, define directory or file
chown -R www-data:www-data /var/www
chmod -R 755 test/ # uga+rwx, u=wg
chmod -R 6711 test/ # setgid and setuid bit

create dir, mv, cp, touch

mkdir -p  1/2/3 # create: p stands for parents
rm -rf 1 #remove(dir and file): r stands for recursive, f stands for force
mv 1 p/o/ # move file and directory`
mv 1 p # rename file directory
cp -r -v 1/  o/ # copy
touch touched.txt # change file access time , if file does not exist will make it.

directories

disk usage and information

df (report file system disk space usage)
  • options :
    • -h : print sizes in human readable format (e.g., 1K 234M 2G)
    • -H : likewise, but use powers of 1000 not 1024
    • -i : list inodes
df -h
du (estimate file space usage)
  • options :
    • -h : print sizes in human readable format (e.g., 1K 234M 2G)
    • -H : likewise, but use powers of 1000 not 1024
    • -c : total
    • -s : summerize
    • --max-depth
    • --time
du -h -c /home/arvin/

compress and extract

tar
  • options :
    • -v : verbose
    • -x : extract
    • -f : file
    • -z : gzip, -j : bzip2
    • -c : create, -r : append, --delete : delete from archive
tar -cvfj test.tar.bz /home 1.txt 2.txt
tar -xvf test.tar.bz
tar -rf test.tar.bz 3.txt

files

search

grep (print lines matching a pattern)
  • options :
    • -L : list not matched files
    • -l : list matched files
    • -c : count
    • -e : regex
    • -i : ingore case
    • -v : invert match
    • -n : show matched line number
    • -r : recursive
    • -w : word
    • -x : line
grep -r -n -c -e "[^gnu].*x" .
find (search for files in a directory hierarchy - find is slow)
  • options:
    • -type: (d: directory, f: file)
    • -name (-iname : ignore case)
    • -o or, -not (!)
    • -perm
      • /a=x
      • /u=r
      • 0566
      • sgid (2564)
    • -exec
    • -user, -group
    • -mtime (modified files by day), -atime (accessed files by day)
    • -cmin (changed by minutes), -amin, -mmin
    • -size
find ./test -name 'abc*' ! -name '*.php'
find ./test -iname "*.Php"
find ./test -not -name "*.php"
find -name '*.php' -o -name '*.txt'
find . -type f ! -perm 0777
find /home/bob/dir -type f -name *.log -size +10M -exec rm -f {} \;
locate (find files by name)
  • locate does not check whether files found in database still exist. locate can never report files created after the most recent update of the relevant database.
  • options:
    • -n : limit lines
    • -c : count
    • -i : ignore case ‍‍‍‍‍‍```bash locate -i text.txt 
    * -S : review locate db
* -d : change db path (-d [dbpath])
  • update db : updatedb files: /etc/updatedb.conf /var/lib/mlocate/mlocate.db

To create a private mlocate database as an user other than root, run

updatedb -l 0 -o db_file -U source_directory

manipulate

  • copy and convert files 1- dd options:

2- iconv

3- sed

read

cat (concatenate files and print on the standard output,Copy standard input to standard output.)
  • options:
    • -n : number all output lines
    • -A : equivalent to -vET
    • -E : display $ at end of each line, -e:-vE
    • -T : display TAB characters as ^I, -t: -vT
    • -v : use ^ and M- notation, except for LFD and TAB
cat test test1
cat -n test
more, less, sort

1- more (file perusal filter for crt viewing), less (opposite of more)

more file1
tail -F /var/etc/nginx/access.logs | more

2- sort (sort lines of text files) * options: * -n : numeric-sort * -r : reverse * -k : sort by column number * -t : field separator * -u : unique * -h : human-numeric-sort bash sort file1 file2 sort file1 sort -r file1 sort -t "," -nk3 file1.csv sort -u file1 ls -alh | sort > sorted.text

wc (count files or standard output)
  • options:
    • -l : lines
    • -w : words
    • -m : chars
    • -c : bytes
wc -l file1
tail (last line of files)
  • options :
    • -F : follows and retry to connect ( -f --retry)
tail -F -n 20 /var/log/nginx/access.log
head (output the first part of files)
head -n 20 /var/log/nginx/access.log
split (split a file into pieces)
  • options
  • -l : customize line (ex -l1200)
  • -b : file size (ex: -b 500M)
  • -n : Generate n chunks output files (ex -n5)
  • -e : Prevent Zero Size Split output files in below example ngx is prefix of generated file
split /var/log/nginx/access.log ngx

merge splited files

cat Split_IS0_a* > Windows_Server.iso
join (join lines of two files on a common field)

  • options

    • -1 (field of first file)
    • -2 (field of second file)
    join -1 2 -2 1 wine.txt reviews.txt

    sorted

    join -1 2 -2 1 <(sort -k 2 wine.txt) <(sort reviews.txt)
    • -t (specify a field separator for joining)
    join -1 2 -2 3 -t , names.csv transactions.csv
paste (paste - merge lines of files)
paste file1 file2

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