shebang = sharp-bang = #!
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 $@ ~/backup && rm $@'
unalias
command
&& yu
|| huo
-eq =
-ne !
-gt >
-lt <
-ge >=
-le <=
9. if condition;
then
commands;
fi
if conditon;
then
commands;
else if condition; then
commands;
else
commands;
fi
10.
find
find . -type f -print
file type : f l d c b s p
-atime
-mtime
-ctime
find . -type f -atime -7 -print
-amin
-mmin
-cmin
find . -type f -amin +7 -print
-newer
find . -type f -newer file.txt -print
find . -type f -size +2k
-2k
2k
find . -type f -perm 644 -print
find . -type f -name "*.php" ! -perm 644 -print
find . -type f -user slynux -print
find . -type f -name "*.swp" -delete
find . -type f -user root -exec chown slynux { } ;
find . -type f -name '*.c' -exec cat { } ;>all_c_files.txt
find . -type f -name '*.c' -exec cat { } >all_c_files.txt ;
find . -type f -name '*.c' -exec cat { } >all_c_files.txt +
find . -type f -mtime +10 -name "*.txt" -exec cp { } OLD ;
find . -type f -name "*.txt" -exec printf "text file: %s " { } ;
11. xargs
echo "split1Xsplit2Xsplit3X" | xargs -d X
echo "splitXsplitXsplitXsplit" | xargs -d X -n 2