Homework & Coursework Questions

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1. The problem statement, all variables and given/known data:

I need to write one c-shell command that does the following:
using the unix "find" command , i need to find all the files, from the current directory and downwards, whose name end with .txt and that contain the string "some text", and for each file that is found, print the first 4 letters of its name.

again, this is supposed to be done in one c-shell command.


2. Relevant commands, code, scripts, algorithms:

i am asked to use the "find" command


3. The attempts at a solution (include all code and scripts):

i managed to write a command that finds all the files whose name ends with .txt and that contain the string "some text", and for each file that is found, prints its name.
with this command:
find -name *.txt -exec grep -h "some text" {} \;

but i couldn't find a way to only print the first 4 letters of each file name.


4. Complete Name of School (University), City (State), Country, Name of Professor, and Course Number (Link to Course):

i am a student in Tel-Hai college in northern Israel.
the professor is Guy Leshem.


Note: Without school/professor/course information, you will be banned if you post here! You must complete the entire template (not just parts of it).

Code:

| cut -c1-4

To get the filename I think you should be using "grep -l" not "grep -h".
Enclose the wildcard filename in single quotes to cause "find" to expand the filenames not Shell.
Confine the search to files "-type f".

Code:

find -type f -name '*.txt' -exec grep -l "some text" {} \;

I dont' write "csh" code, but you will need to process each filename with the "basename" command to remove the directory tree information from each filename, then use "cut" to shorten each filename.

thank you very much

You may have completed your assignment, but this is worth knowing: the xargs command comes in very handy here:

Code:

find -type f -name '*.txt' | 
grep -l "some text" |
sed -p 's/^\(....\).*/\1/'

The -l option of grep prints only the filename of matching files. The sed command is another way of achieving the effect used by "cut", above.

The reason for xargs is efficiency: instead of calling "grep" for each file, as find does, xargs calls grep only as many times as needed given the OS constraints (length of command line). In everyday work, I use it once a day at least.

thanks again