liudepengzhgd的专栏

grep "hello" file.txt | wc -l

点击打开链接 if condition then code else code fi codition ;is also right

URL:http://www.linuxdiyf.com/viewarticle.php?id=20338 First line: #!/bin/sh make ./ avaliable: chmod +x pre.sh comments: # #!/bin/sh a="Hello world!" #Variable echo $a #Print $a echo "$a my n

》： vocer 》》： additional

call command: ./isnump_n n get parameters count: $# get n(first true parameter): $1

exit n: 0:success n is optional then : $?=n if there is no n ,$? will remain the previous value. Parent process use $?.

wiki Syntax: test expression or [ expression ] (space is essential) example: if [ $# -eq 0 ] of if test $1 -gt 0