GNU/Linux notes
From OriWiki
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realpath to current directory
readlink -f .
or if realpath is installed
realpath .
determining the path of which a script resides
The following seems to be problematic:
dirname $0
if the script is run using a full path, everything works fine. relative path.. problematic .. source -- give the path of the shell interpreter (/bin/ or something..)
hierarchical copy of directory content
the following example shows that 'cp -r dir1/* dir2/' overwrites any files in the hierarchy but leaves existing files in a subdirectory untouched
[ori@sun2 tmp]$ mkdir dir1 [ori@sun2 tmp]$ mkdir dir2 [ori@sun2 tmp]$ mkdir dir1/dir [ori@sun2 tmp]$ mkdir dir2/dir [ori@sun2 tmp]$ echo "created in dir1" > dir1/dir/f1 [ori@sun2 tmp]$ echo "created in dir1" > dir1/dir/f2 [ori@sun2 tmp]$ echo "created in dir2" > dir2/dir/f1 [ori@sun2 tmp]$ echo "created in dir2" > dir2/dir/f3 [ori@sun2 tmp]$ cp -r dir1/* dir2/ [ori@sun2 tmp]$ cd dir2 [ori@sun2 dir2]$ cd dir [ori@sun2 dir]$ ls f1 f2 f3 [ori@sun2 dir]$ cat * created in dir1 created in dir1 created in dir2
create a new account
Login as root
useradd <username>
changing the new account's password:
passwd <username>
source and .
These two are the same:
source shellScript.sh . shellScript.sh
And they mean that the shell script will run and effect the current shell (not in a new spawned child shell)
wc
recursive wc:
wc -l `find . -name *.cpp`
copy cd
sudo umount /dev/cdrom readcd dev=/dev/cdrom f=file.iso
on Gutsy Gibbon, the following seemed to work:
readcd dev=/dev/cdrom1 f=file.iso
ls sorted by modification time
ls -t
Combined with the detailed view: ls -lt
which packages are installed on the system?
pkginfo
