shell1

Posted 2021-02-12 zhg1016

1.echo $PATH

   export PATH="$PATH:/home/user/bin"

PREPEND

prepend() { [ -d "$2" ] && eval $1="$2‘:‘$$1" && export $1; }

2.echo -e "e[1;31m This is red text e[0m"

0 black 30 red 31 green 32 yellow 33 bule 34 yangred 35 qing 36 white 37

backgroud color 0 black 40 red 41 green 42 y 43 bule 44 yangred 45 qing 46 white 47

 

3.env

cat /proc/$PID/environ

pgrep gedit  -> serch process ID

4.let (()) [  ]   bc

echo "scale=2;22/7" | bc

5.$?

echo $?

6. command | tee FILE1 FILE2  | otherCommand

cat a* | tee -a out.txt | cat -n     # -a  add

7.declare -A ass_array

8.alias rm=‘cp [email protected] ~/backup && rm [email protected]‘

unalias

command