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Linux tips

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= Paths & I/O & files =
= Paths & I/O & files =
-
== Paths & directories: pwd, mkdir, rmdir, rm ==
+
== Paths & directories: <tt>pwd, mkdir, rmdir, rm</tt> ==
* <tt>pwd</tt> returns current directory
* <tt>pwd</tt> returns current directory
* relative to current directory: e.g. <tt>ls subdir/subsubdir</tt> or <tt>ls ../whatever/</tt>
* relative to current directory: e.g. <tt>ls subdir/subsubdir</tt> or <tt>ls ../whatever/</tt>

Revision as of 11:27, 5 March 2013

Contents

Paths & I/O & files

Paths & directories: pwd, mkdir, rmdir, rm

  • pwd returns current directory
  • relative to current directory: e.g. ls subdir/subsubdir or ls ../whatever/
  • absolute ls ~user/path or ls /home/user/path
  • mkdir: create directory. e.g. mkdir ~/newdir or with subdirs mkdir -p ~/new/newsub/newsubsub
  • rmdir dirname or if not empty rm -fr dirname

Permissions

$ ls -l /home
drwxr-x---  69 barriot    gsi   4.0K Mar  5 12:09 barriot
drwx------   2 root       root   16K Jul 12  2010 lost+found
drwxr-xr-x  36 micas      stage 4.0K Jul 31  2012 micas
...
 
[barriot@gamborimbo ~]$ ls -lh Documents/TEACHING/2012-2013/M1-MABS/Graph/TP3-igraph.layout/
total 80K
drwxr-xr-x 1 barriot gsi 4.0K Mar 14  2012 HDE.old
-rw-r--r-- 1 barriot gsi  24K Mar 14  2012 91347.nwk
-rw-r--r-- 1 barriot gsi  942 Mar  1 16:02 Cleandb_Luca_1_S_1_1_65_Iso_Tr_1-CC1.cod
-rw-r--r-- 1 barriot gsi  28K Sep  7  2010 Cleandb_Luca_1_S_1_1_65_Iso_Tr_1-CC1.gr
-rw-r--r-- 1 barriot gsi 2.3K Sep  7  2010 Cleandb_Luca_1_S_1_1_65_Iso_Tr_1-CC1.tgr
-rw-r--r-- 1 barriot gsi 4.7K Mar  5 11:42 cmds.R
-rw-r--r-- 1 barriot gsi  871 Mar 14  2012 sample_tree_with_branchlengths.nwk
-rwxr-xr-x 1 barriot gsi  670 Mar 14  2012 drawTree.py
-rw-r--r-- 1 barriot gsi 5.6K Feb 27 16:57 Tree.py

First character corresponds to file type. d for directory, - for a regular file, ... Then by 3 for the owner (user), the group and the others.

For a regular file :

  • r for permission to read
  • w for permission to modify
  • x for being able to execute the file (binary executable or script)

For a directory :

  • r to be able to read the content (list files in the directory)
  • w to be able to add or remove files
  • x to be able to pass through that directory, i.e. cd to that dir or a subdir

Modify ownership of a file or directory :

# change owner
chown newuser file
# recursive
chown -R newuser directory
# change group
chgrp newgroup filename
# change both
chown newuser.newgroup filename

Modify permissions:

# numeric notation: r=4, w=2, x=1, thus for rwx-r-x---
chmod 760 file
# on a sub directory
chmod -R 760 dirname
# symbolic notation:
chmod u=rwx,g=rx,o= filename
# add execute permission for all:
chmod a+x filename
# revoke write permission for others:
chmod o-w filename

permissions, cat, redirection, head, tail, more, less, tac, sed, grep, cut, find, stat, file


Processes

ps, jobs, Ctrl-C/Z/D, top, kill, killall, nohup, disown, &

shell

variables, test, $?, for, if, function, $(cmd), && ||

archive

tar, bzip, gzip, rsync