[Linux] basic command 1

cat, tac

• Shows the contents of the file.

• Option

  • -n : number all output lines
  • -b : number nonempty output lines
  • > : If the file exists, it is overwritten
  • >> : append to the end of the file

tee, nl

• tee -a : append to the end of the file
• nl == cat -b
• -i10, -v100, -w10

head, tail

• head
  • head a : 10 lines from head
  • head -n 10 a : 10 lines from head
  • head -n +10 a : 10 lines from head
  • head -n -5 a : subtract the last 5 lines
• tail
  • tail b : 10 lines from tail
  • tail -n 10 b : 10 lines from tail
  • tail -n -10 b : 10 lines from tail
  • tail -n +3 b : from 3 lines to end line

split

• Opiton
  • -l
  • -C
  • -a
  • -d
  • –additional-suffix
  • –numeric-suffixes

csplit, wc

• Option
  • csplit -f aa_
  • csplit k /REGEXP/ {*}
  • csplit k %REGEXP%

ls

• Option
  • -a : all
  • -A : almost all (no . ..)
  • -l : long
  • -h : human-readable

  • -F : (one of */=>@

    )

  • -i : inode

  • -R : recursive

  • -S : size
  • -r : reverse
  • -t : time
  • -t :modifiction time
    • -u : access time
    • -c : change -time

---

Reference

• –help