#!/bin/sh if [ "$SHELL" = "/bin/bash" ]; then echo "your login shell is the bash (bourne again shell)" else echo "your login shell is not bash but $SHELL" fi
#!/bin/sh ftype=`file "$1"` case "$ftype" in "$1: Zip archive"*) unzip "$1" ;; "$1: gzip compressed"*) gunzip "$1" ;; "$1: bzip2 compressed"*) bunzip2 "$1" ;; *) error "File $1 can not be uncompressed with smartzip";; esac
select var in ... ; do break done .... now $var can be used .... 下面是一個例子： #!/bin/sh echo "What is your favourite OS?" select var in "Linux" "Gnu Hurd" "Free BSD" "Other"; do break done echo "You have selected $var"
下面是該腳本運行的結果：
What is your favourite OS? 1) Linux 2) Gnu Hurd 3) Free BSD 4) Other #? 1 You have selected Linux
您也可以在shell中使用如下的loop表達式：
while ...; do .... done
while-loop 將運行直到表達式測試為真。will run while the expression that we test for is true. 關鍵字"break" 用來跳出循環。而關鍵字」continue」用來不執行餘下的部分而直接跳到下一個循環。
for-loop表達式查看一個字元串列表 (字元串用空格分隔) 然後將其賦給一個變數：
for var in ....; do .... done
在下面的例子中，將分別列印ABC到屏幕上：
#!/bin/sh for var in A B C ; do echo "var is $var" done
下面是一個更為有用的腳本showrpm，其功能是列印一些RPM包的統計信息：
#!/bin/sh # list a content summary of a number of RPM packages # USAGE: showrpm rpmfile1 rpmfile2 ... # EXAMPLE: showrpm /cdrom/RedHat/RPMS/*.rpm for rpmpackage in $*; do if [ -r "$rpmpackage" ];then echo "=============== $rpmpackage ==============" rpm -qi -p $rpmpackage else echo "ERROR: cannot read file $rpmpackage" fi done
#!/bin/sh # we have less than 3 arguments. Print the help text: if [ $# -lt 3 ] ; then cat < ren -- renames a number of files using sed regular expressions
USAGE: ren 'regexp' 'replacement' files...
EXAMPLE: rename all *.HTM files in *.html: ren 'HTM$' 'html' *.HTM
HELP exit 0 fi OLD="$1" NEW="$2" # The shift command removes one argument from the list of # command line arguments. shift shift # $* contains now all the files: for file in $*; do if [ -f "$file" ] ; then newfile=`echo "$file" | sed "s/${OLD}/${NEW}/g"` if [ -f "$newfile" ]; then echo "ERROR: $newfile exists already" else echo "renaming $file to $newfile ..." mv "$file" "$newfile" fi fi done
#!/bin/sh help() { cat < This is a generic command line parser demo. USAGE EXAMPLE: cmdparser -l hello -f -- -somefile1 somefile2 HELP exit 0 }
while [ -n "$1" ]; do case $1 in -h) help;shift 1;; # function help is called -f) opt_f=1;shift 1;; # variable opt_f is set -l) opt_l=$2;shift 2;; # -l takes an argument -> shift by 2 --) shift;break;; # end of options -*) echo "error: no such option $1. -h for help";exit 1;; *) break;; esac done
echo "opt_f is $opt_f" echo "opt_l is $opt_l" echo "first arg is $1" echo "2nd arg is $2"
您可以這樣運行該腳本：
cmdparser -l hello -f -- -somefile1 somefile2
返回的結果是：
opt_f is 1 opt_l is hello first arg is -somefile1 2nd arg is somefile2
#!/bin/sh # vim: set sw=4 ts=4 et: help() { cat < b2h -- convert binary to decimal
USAGE: b2h [-h] binarynum
OPTIONS: -h help text
EXAMPLE: b2h 111010 will return 58 HELP exit 0 }
error() { # print an error and exit echo "$1" exit 1 }
lastchar() { # return the last character of a string in $rval if [ -z "$1" ]; then # empty string rval="" return fi # wc puts some space behind the output this is why we need sed: numofchar=`echo -n "$1" | wc -c | sed 's/ //g' ` # now cut out the last char rval=`echo -n "$1" | cut -b $numofchar` }
chop() { # remove the last character in string and return it in $rval if [ -z "$1" ]; then # empty string rval="" return fi # wc puts some space behind the output this is why we need sed: numofchar=`echo -n "$1" | wc -c | sed 's/ //g' ` if [ "$numofchar" = "1" ]; then # only one char in string rval="" return fi numofcharminus1=`expr $numofchar "-" 1` # now cut all but the last char: rval=`echo -n "$1" | cut -b 0-${numofcharminus1}` }
while [ -n "$1" ]; do case $1 in -h) help;shift 1;; # function help is called --) shift;break;; # end of options -*) error "error: no such option $1. -h for help";; *) break;; esac done
# The main program sum=0 weight=1 # one arg must be given: [ -z "$1" ] && help binnum="$1" binnumorig="$1"
while [ -n "$binnum" ]; do lastchar "$binnum" if [ "$rval" = "1" ]; then sum=`expr "$weight" "+" "$sum"` fi # remove the last position in $binnum chop "$binnum" binnum="$rval" weight=`expr "$weight" "*" 2` done
#!/bin/sh # vim: set sw=4 ts=4 et: ver="0.1" help() { cat < rotatefile -- rotate the file name
USAGE: rotatefile [-h] filename
OPTIONS: -h help text
EXAMPLE: rotatefile out This will e.g rename out.2 to out.3, out.1 to out.2, out to out.1 and create an empty out-file
The max number is 10
version $ver HELP exit 0 }
error() { echo "$1" exit 1 } while [ -n "$1" ]; do case $1 in -h) help;shift 1;; --) break;; -*) echo "error: no such option $1. -h for help";exit 1;; *) break;; esac done
# input check: if [ -z "$1" ] ; then error "ERROR: you must specify a file, use -h for help" fi filen="$1" # rename any .1 , .2 etc file: for n in 9 8 7 6 5 4 3 2 1; do if [ -f "$filen.$n" ]; then p=`expr $n + 1` echo "mv $filen.$n $filen.$p" mv $filen.$n $filen.$p fi done # rename the original file: if [ -f "$filen" ]; then echo "mv $filen $filen.1" mv $filen $filen.1 fi echo touch $filen touch $filen
