ls: list files and dirs in current dir

• -a display all files
• -l display in list
• -t sort by edit time

mv: move / rename

• mv source target

cp: copy files / dirs

• -a copy all properties
• -r recursion
• -f forcible

rm remove file

• -rf recursion and forcible

echo: display content

• -e escape string

cat: display or combine file

• -n display line numbers
• cat file1 > file2 : combine file1 to file2

find

• -o combine two paras
• -name figure the file name
• -iname similar to -name, ignore low/upcase
• ! not

• -type file type

  • f normal
  • l linking
  • d dir
• -maxdepth the maximumal depth of dir

• -size figure size of file

  • +10k: >10k
  • -10k: <10k
  • 10k: ==10k
• -empty empty file
• -delete delete found files
• -user
• -exec execute commands

grep: regular expression

• -v reverse
• -o only output matched text
• -E use extended regular expression
• -c count number of matched lines
• -n display line numbers of matched line

seq: generate sequence

• -f format
• -s separator
• -w same width (add "0")

wc: count file number of lines and words

• -c display bytes
• -l display line numbers only
• -w display word number only

tar

• -c create new backups
• -v display the progress
• -f filename
• -z gzip
• -j bzip
• -x uncompress
• -C figure a dir

sort: sort txt

• -u ignore same lines
• -k column of sort key
• -t separator between columns