Bash and batch programming

Wanna loop over files in bash and perform a cmd on those files?

# (where $i is replaced by the name of the file)
for i in ./*.conf; do cmd -c $i; done

# (where {} is replaced by the name of the file)
find . -name *.conf -exec cmd {} \;

Cutting up file/path strings in bash

Get directory portion of path

dirportion = ${path%/*}

Get the filename of path

filename = ${path##*/}

Get the basename of the file (without extension)

basename = ${path%%.*}

Get the extension of the path

ext = ${file#*.}

${variable%pattern}

Trim the shortest match from the end

${variable##pattern}

Trim the longest match from the beginning

${variable%%pattern}

Trim the longest match from the end

${variable#pattern}

Trim the shortest match from the beginning

Wanna make a CGI script in bash?

if [ expression ]
then
   commands
elif [ expression2 ]
then
   commands
else
   commands
fi

#This program lists the parameters that were passed to the program, along with the parameter number.
 
count=1
while [ -n "$*" ]
do
   echo "This is parameter number $count $1"
   shift
   count='expr $count + 1'
done

case $1 in
-i)
   count='grep ^i $2 | wc -l'
   echo "The number of lines in $2 that start with an i is $count"
   ;;
-e)
   count='grep ^e $2 | wc -l'
   echo "The number of lines in $2 that start with an e is $count"
   ;;
*)
   echo "That option is not recognized"
   ;;
esac

# In this form, the for statement executes once for each item in the list. 
# This list can be a variable that contains several words separated by spaces, 
# or it can be a list of values that is typed directly into the statement. Each 
# time through the loop, the variable var1 is assigned the current item in the 
# list, until the last one is reached.
for var1 in list
do
   commands
done

for i in `sed -e 's/,.*$//g' < upgrade/4.1.9-4.1.11/file.lst`; do chmod 666 $i ; done

Find and replace using find and sed

find ./ -type f -exec sed -i ’s/string1/string2/’ {} \;