UNIX

UNIX ShellUNIX Shell - , UNIX, . , , .

POSIXPOSIX (ISO/IEC 9945) (Portable Operating System Interface for Unix - Unix) , . POSIX .

POSIX 3. , ( , ), (if, case, ||, &&) (for, for in, while, until) , . , (vi).

UNIX ShellsBourne shell compatiblesh, ash, bash, dash, ksh, zshC shell compatiblecsh, tcshExotices (functional), psh (Perl), pysh (Python)

Bourne Shell Bell Labs 7- UNIX (UNIX Version 7, 1977). ALGOL 68

"Nobody really knows what the Bourne shell's grammar is. Even examination of the source code is little help." Tom Duff

C Shell ( ) 1970 C. sh

Korn Shell 1980. Bourne shell C shell.

The POSIX standard specifies its standard shell as a strict subset of the Korn shell

Bourne Again Shell (bash) GNU sh 1989 . csh ksh.

shell Linux MacOS

Bash features $RANDOM $PPID

echo - ( stdout)printf - , echoread - (stdin),

Hello World!echo Hello World!

printf "%s\n" "Hello World"

:$ echo -e "a\n"a

-h, --help -? ( )

: ls -ltra

help COMMAND COMMANDman COMMAND COMMANDinfo COMMAND

d pwd mkdir rm cp touch ls

more, lesshead, tailwcsortteefindlocategrep

Tab Tab

0 (stdin) . >grep 'apt' < a 1 (stdout) - >ls > a.txtgrep 'apt' < a > b 2 (stderr) - 2>ping -c 5 google.com > result.txt 2> error.txt

> - >> -

(pipe) . . : |.

cat filename | grep something

HotkeysCtrl-C - SIGINT, .Ctrl-D - (EOF).Ctrl-Z - SIGTSTP, .

, - .txt. cal. , . ip.txt IP . res.txt, err.txt. , , r. , .