Shell command to read and output data

Shell command to read data and output data [plain] www.2cto. comshell scripts read data in several ways: 1. keyboard Input. default value: 2. read from file 3. the echo function is passed through pipeline commands: \ c: No line feed \ f: paper feed \ t: hop grid \ n: line feed...
The Shell command reads data and the output data [plain] www.2cto.com shell script reads data in several ways: 1. keyboard Input. default value: 2. read from file 3. the echo passing function through pipeline commands: \ c: do not wrap \ f: paper feed \ t: hop grid \ n: line feed \ escape, for example: "\"/dev/rmt0 "\" translated as, "/dev/rmt0" read: reads information from a line of text on the keyboard or file, and assign it to a variable. [Developer]/> read name hello I am a regular user [developer]/> echo $ name hello I am a regular user [developer]/> cat: role, 1. show file content, 2. create a file, 3. display control characters. 1. show the file content cat filename | more cat filename | pg 2. create a file cat> filename 3. display Control character cat-v filename pipe: you can use the pipe to pass the output of one command to another as the input. Format: Command 1 | Command 2 example: [developer]/usr/xxxx/ytcclb> who | awk '{print $1 "\ t" $2}' xxxx ttyp0 xxxx ttyp1 xxxx ttyp2... xxxx ttyp55 [developer]/usr/xxxx/ytcclb> df-k | awk '{print $1}' | grep-v "Filesystem"/dev/root/dev/boot [development]/usr/xxxx/ytcclb> df-k | awk '{print $1}' | grep-v "Filesystem" | sed s'/\/dev \/// g'root boot [development]/usr/xxxx/ytcclb> tee command: one copy of the output is delivered to the standard output, and the other copy is copied to the corresponding file. Tee-a file-a: append to the end of the file. [Developer]/usr/xxxx/ytcclb> who | tee who. out saves the data found by the who command to the who. out file. File redirection: command> filename redirects the standard output to a new file. command> filename redirects the standard output to a file (append) command 1> fielname redirects the standard output to a file command> filename 2> & 1 redirects the standard output and standard error together to a file command 2> filename redirects the standard error command 2> filename in a file redirects the standard output to a file (append) command> filename 2> & 1 redirects the standard output and standard error together to a file (append) command <filename> filename2 uses the command file as the standard input, output command using the filename2 file as the standard <filename The ilename file is used as the standard input command <delimiter reads from the standard input, until the delimiter command <& m redirects the file descriptor m to the file descriptor m as the standard input command> & m redirects the standard output to the file descriptor m command <&-redirects the standard output of the disabled standard input to the file descriptor m. 1. append the output of many commands to a file ls-l | grep ^ d> files. out ls account *> files. out [development]/usr/xxxx/ytcclb> ls-l null.txt-rw-r -- 1 xxxx group 3 Nov 15 07 null.txt [development]/usr/xxxx/ytcclb> chmod u + x null.txt chmod: WARNING: cannot access + x: No such file or direct There is a space between ory (error 2) u and + x! [Development]/usr/xxxx/ytcclb> chmod u + x null.txt [development]/usr/xxxx/ytcclb> ls-l null.txt-rwxr -- r -- 1 xxxx group 3 Nov 15 16: 07 null.txt