OTHER FILE HANDLING COMMANDS

type 

- show where the source of a command is: e.g.
$ type sendmail
sendmail is /usr/sbin/sendmail
This command is merely an alias for 'whence -v'

whence 

- show where the source of a command is: shell builtin command. See type
Use option: -v for verbose mode

which 

- show where the source of a command is held. Almost the same as type and whence

chmod 

- change file permissions. e.g.
$ chmod 666 handycommands
changes the permissions (seen by ls -l) of the file handycommands to -rw-rw-rw-
r = 4, w = 2, x = 1. In the above example if we wanted read and write permission for a particular file then we would use r + w = 6. If we then wanted to have the file have read-write permissions for User, Group and All, then we would have permissions of 666. Therefore the command to change is that above.
$ chmod 711 a.out
Changes permissions to: -rwx--x--x
Additional explanation of file permissions and user/group/all meaning are given in the description of ls -l
You may specify chmod differently - by expressing it in terms of + and - variables. For example
$ chmod u+s /usr/bin/su
will modify the "sticky bit" on su, which allows it to gain the same access on the file as the owner of it. What it means is "add s permission to user". So a file that started off with permissions of "-rwxr-xr-x" will change to "rwsr-xr-x" when the above command is executed. You may use "u" for owner permissions, "g" for group permissions and "a" for all.

chown 

- Change ownership of a file. Must be done as root. e.g.
chown informix *.dat # change all files ending .dat to be owned by informix

chgrp 

- Change group ownership of a file. Must be done as root. e.g.
chgrp sys /.netrc # change file /.netrc to be owned by the group sys

mvdir 

- move a directory - can only be done within a volume group. To move a directory between volume groups you need to use mv -r
or find -print | cpio -pdumv ; rm -r

cpdir 

- copy a directory. See mvdir

rmdir 

- this is crap - use rm -r instead

mkdir 

- Creates a directory. e.g.
$ mkdir /tmp/jon/ # create directory called /tmp/jon/ 

find  -name "searchkey" -print

- search for files - e.g.
$ find . -name "system.log" -print # will find all files (with full path names) called system.log - Wildcards are allowed, e.g.
$ find /tmp -name "sl.*" -atime +0 -print # will print out all files in /tmp/ that start sl. and which haven't been accessed for a day. Helpful for finding lost files, or finding stuff in enormous directories. Other useful options include:

• -atime + - finds files that haven't been accessed for 1+days also, ctime (creation time) and mtime (modify time)
• -prune - stay in current directory - don't look in dirs off the directory specified in path names - e.g.
  $ find /tmp -user "compgnc" -prune -print # will find all files in /tmp which user compgnc owns and will not search lower directories (e.g. /tmp/usr)
• -size + - finds files that are bigger than
• -exec rm {} \; - remove all files found...dangerous command - e.g.
  $ find /tmp -name "sl.*" -atime +0 -prune -print -exec rm {} \; # will remove all files in /tmp starting 'sl.' that haven't been accessed for a day. Spacing of this command is important! Most exec commands are possible:
  $ find /usr2/calltest -name "*.4gl" -print -exec grep "CHECK" {} \; | pg
• -ok - like exec only it prompts for confirmation after each occurence. e.g.
  $ find /tmp/disk7 -name "*" -print -ok doswrite -a {} {} \; # Please note that you MUST end any exec or ok option with an escaped semicolon (\;).
• -user - finds all files owned by
• -group - finds all files with a group of

ln -s

- create a symbolic link to a different directory from current directory: e.g.
$ ln -s /usr/uniplex/compgnc /u/compgnc/uni # would create a link called 'uni' in the directory /u/compgnc. From then on, typing cd uni would cd to /usr/uniplex/compgnc. You can also give two files the same name. e.g.
$ ln make.e_enquiry makefile # would link the two files so that they are identical, and when you change one, you change the other. You may also create a symbolic link to a host(!). Instead of typing 'rlogin hpserver' every time, by typing
$ ln -s /usr/bin/rsh hpserver # will create a link so that whenever you type 'hpserver' it will execute a remote shell on the machine.
Option -f forces the link to occur

head -

- prints out the first few line of a file to screen. Specify number to indicate how many lines (default is 10). e.g. If you sent something to a labels printer and it wasn't lined up, then you could print the first few labels again using:
$ head -45 label1.out | lp -dlocal1

tail -

- prints out the end of a file. Very similar to head but with a very useful option '-f' which allows you to follow the end of a file as it is being created.e.g.
$ tail -f vlink.log # follow end of vlink.log file as it is created.

wc -

- Word Count (wc) program. Counts the number of chars, words, and lines in a file or in a pipe. Options:

• -l (lines)
• -c (chars)
• -w (words)

To find out how many files there are in a directory do ls | wc -l

split -

- Splits a file into several files.e.g.
$ split -5000 CALLS1 # will split file CALLS1 into smaller files of 5000 lines each called xaa, xab, xac, etc.

tr 

- translates characters. e.g.
$ cat handycommands | tr "\t" " " # will take the file handycommands and translate all tabs into spaces. Useful when messing about with awk or you need to convert some input (e.g. that from tty) to a unique filename that does not contain special characters. e.g.
$ tty | tr "/" "." # produces for example .dev.pts.7

od 

- od converts nasty (binary save) files into character representations. Useful when back-compiling, examining raw .dat files,etc. Use with option '-c' for character display (recommended).

script

- starts recording everything in the shell to a file by default 'typescript'. Press ^D to finish the script. Provides a log of everything used. Has almost the same effect as $ ksh | tee typescript
Used for debugging shells, seeing error messages which flash off the screen too quickly, etc.

cut

- cut's the file or pipe into various fields. e.g.
$ cut -d "|" -f1,2,3 active.unl # will take the file active.unl which is delimited by pipe symbols and print the first 3 fields options:

• -d
• -f

Not too useful as you can't specify the delimiter as merely white space (defaults to tab) Alternatively, you can 'cut' up files by character positioning (useful with a fixed width file). e.g.
$ cut -c8-28 "barcode.txt" # would cut columns 8 to 28 out of the barcode.txt file.

paste

- paste will join two files together horizontally rather than just tacking one on to the end of the other. e.g. If you had one file with two lines:
Name:
Employee Number:and another file with the lines:
Fred Bloggs
E666then by doing:
$ paste file1 file2 > file3 # this would then produce (in file3).
Name: Fred Bloggs
Employee Number: E666Note that paste puts horizontal tabs between the files, so you may need a sed 's/   //g' command to get rid of these.

sort 

- sorts the information from the file and displays the result on standard output (stdout). e.g.
$ sort /tmp/list_of_names # will sort the file into alphabetical order, and display it to the screen. Useful with option '-u' to filter out duplicates.

uniq 

- filters out all duplicate lines from a file or input stream (file or stream must be sorted!). Useful with option -c which merely produces a count of unique lines.

ex 

- ex is an old line editor, and almost never used now (similar to DOS edlin if you remember that - me, I've repressed it). You are most likely to come across ex within the vi editor - all commands beginning with a colon (:) are ex commands