To read input to a command and process it in some way:
#!/bin/sh # usage: fsplit file1 file2 total=0; lost=0 while read next do total=`expr $total + 1` case "$next" in *[A-Za-z]*) echo "$next" >> $1 ;; *[0-9]*) echo "$next" >> $2 ;; *) lost=`expr $lost + 1` esac done echo "$total lines read, $lost thrown away"
The user types the command:
fsplit file1 file2
They then enter lines of text and issue an EOF instruction. The script then processes the lines as follows:
A line with at least one letter is appended to file1; any line with at least one digit and no letters is appended to file2. All other lines are thrown away.
To read commands from the terminal and process them:
#!/bin/sh # usage: process sub-directory dir=`pwd` for i in * do if test -d $dir/$i then cd $dir/$i while echo "$i:" read x do eval $x done cd .. fi done
The user types the command:
process sub-directory
This script will read and process commands in the named sub-directory. The user is prompted to supply the name of the command to be read in. This command is executed using the the builtin eval function.
To create a command:
#!/bin/sh flag= for i do case $i in -c) flag=N ;; *) if test -f $i then ln $i junk$$ rm junk$$ elif test $flag # true if not null then echo \'$i\' does not exist else >$i fi ;; esac done
This command takes filenames as its parameters. If a file exists it changes the modification date. If no file exists it creates a new one. This script is similar in action to the touch command.
The -c argument lets you specify that you only want to update a file that already exists and not to create one if it doesn't.