Linux Shell Basics (vi)

Six, shell script programming details of the above five parts of the content, in series to increase the understanding of the Shell 01.shell script shell:# #perl #python#php#jsp different scripts to execute different text, the role of execution is not the same; #shell Scripts (UNIX like system has one principle: the shorter the program, the better) #bash csh tcsh Ksh#which startx (View the path to the file)/usr/x11r6/bin/startx#vi ' which startx ' #!/ Bin/sh. #vi/etc/rc.d/rc.sysinit (Modify the system name, color, and so on) #echo $SHELL the # notation in the/bin/bash script, but the # in the first line has a special meaning: such as: The first line of the word printable #, Indicates that this is a bash script in the first line is #, but the second character is not I, which indicates that this is a CSH script the first line character is #, and the second character is! That represents a call to the/usr/bin/python2.2 program specified later to execute the following script 02.shell the normal expression bash itself does not provide regular representation support, only the wildcard character *? Regular expressions can be executed with some commands, such as the introduction of Grep,vi,sed,awk in Linux shell (ii) 03. Interaction with Shell scripts #cd/tmp/ddd/#ls ... #rm-rf * #vi a#!/bin/ Bashecho $ \$1echo $ \$2echo $ \$3echo $# \$\ #echo $? \$\?echo $$ \$\ $wq #chmod a+x a#./a$1$2$30 $# (input number of parameters) 0 $?3061 $$#./a aaa bbb cccaaa $1bbb $2CCC $34 $ #0 $?3064 $$ #vi b#!/b In/bashecho Stop $ $2ing ... #./b httpd stophttp stoping ... #read读入数据给变量 #echo output data #printf output data #vi a#!/bin/bashecho (do input) \$ 1echo $ (do input) \$2echo $ (do input) \$3echo $# (see several parameters) \$\ #echo $? (if the shell command is executed successfully, do not succeed, perform other) \$\?echo $$ \$\ $read-P "please Put yourName "Aaaprinf" $AAA is Fool "#./a AAA bbb cccaaa $1bbb $2CCC $34 $ #0 $?3064 $ $please Input your NAME:BYFBYF is fool#printf "\ t hello\n"Hello#help Printf#man bash ...:p rintf#printf "\a" (produces a sound) 04.bash execution mode 1. Enter the absolute path or relative path of the script/root/bachup./ Bachup2.bash scripts or tcsh and scripts, find the child shell to execute the script bash/root/backup3 with bash or tcsh. Add "." to the path of the script to indicate that there is a script under a path: /backup. /root/backup#vi bpstree |grep-a2-b2 pstreebash--pstree#pstree |grep-a2-b2 pstree#bash./bbash--bash--pstree#chmod a+x Bbash--bash--pstree#vi bexport Bbb=byf (set BBB to the BYF directory and sub-directory environment variable) wq#cat bexport bbb#./bpstree |grep-a2-b2 pstre#echo BBB #. /tmp/b (executed in the current shell script) #. ./b#echo $BBB (take out the variable value of BBB) BYF

Linux Shell Basics (vi)