The above command will set the GID bit on all directories named .svn in the current directory recursively. This makes the group ownership of all .svn folders be the group ownership for all files created in that folder, no matter the user. This is useful for me as the subversion working directory on my server is also the live website and needs to be auto committed to subversion every so often via cron as well as worked on by multiple users. Setting the GID bit on the .svn folders makes sure we don't have a mix of .svn metadata created by a slew of different users.

This one liner; combines all sequentially numbered files; in this example IMG_0001.png to IMG_1121.png by generating the shell script, making the shell script executable and then running the shell script to combine the 1121 png into a single png file named _final.png tested on Mac OS X 10.6.3 with ImageMagick 6.5.8-0 2009-11-22 Q16 http://www.imagemagick.org

The first argument is the interpreter for your script, the second argument is the name of the script to create. Show Sample Output

This will create, in the current directory, a file called 'pk.pem' containing an unencrypted 2048-bit RSA private key and a file called 'cert.pem' containing a certificate signed by 'pk.pem'. The private key file will have mode 600. !!ATTENTION!! ==> this command will overwrite both files if present.

This command is useful to recursively make executable all "*.sh" files in a folder. This command is useful to apply chmod recursively in a determined kind of file.

Create a bash script to change the modification time for each file in 'files.txt' such that they are in the same order as in 'files.txt' File name for bash script specified by variable, 'scriptName'. It is made an executable once writing into it has been completed. Show Sample Output

This function will encrypt a bash script and will only execute it after providing the passphrase. Requires mcrypt to be installed on the system. Show Sample Output

changes group ownership of all files/dirs in /path/to/dir to a project group [projgroup] and then gives the sgid bit to directories in that tree - all subsequently created files will inherit [projgroup]'s gid.

a simple command in order to make iptables rules permanent, run @ sudo!

per comments

Should run with sudo

Uses find to find and chmod directories recursively.

Usage: VBoxBlockBoot [Virtual_Machine] [Block_device] Eg: VBoxBlockBoot WinXP /dev/sdc In another words vm=usb; usb=sdc;sudo umount /dev/$usb* ; sudo chmod 777 /dev/$usb ; VBoxManage storageattach $vm --medium ~/raw-HD-4-VB/$usb.vmdk --type hdd --storagectl "IDE Controller" --device 0 --port 0 ; VBoxManage startvm $vm Where vm --> Name of the virtual machine to start usb --> Block device to use. (/dev/sdc) This can used after setup up a boot loader on to my USB pen drive or HDD (After creating Live USB). Here root privilege is needed but not granted to Virtual Box. Thus we can access all our VM.( If we run VBox as root we can't access our VMs). Root privilege is used to - Unmount the storage device - Chmod to full access (777) Requirements:- 1. Device information file (rawvmdk file) created by the following command. Need to run only once. Not bad to run many. VBoxCreateRawDisk() { VBoxManage internalcommands createrawvmdk -filename ~/.rawHD4VB_`basename "$1"`.vmdk -rawdisk "$1"; } 2. Root privilege to umount & chmod 3. Real storage medium (ie /dev/*) (Non-virtual such as USB HD, pen drive, a partition) 4. A virtual m/c already available (here "usb") vm=usb; usb=sdc;sudo umount /dev/$usb* ; sudo chmod 777 /dev/$usb ; VBoxManage storageattach $vm --medium ~/raw-HD-4-VB/$usb.vmdk --type hdd --storagectl "IDE Controller" --device 0 --port 0 ; VBoxManage startvm $vm VBoxBlockBoot() { sudo umount "$2"*; sudo chmod 777 "$2"; VBoxManage storageattach "$1" --medium ~/.rawHD4VB_`basename "$2"`.vmdk --type hdd --storagectl "IDE Controller" --device 0 --port 0 ; VBoxManage startvm "$1"; } Show Sample Output

If you make a mess (like I did) and you removed all the executable permissions of a directory (or you set executable permissions to everything) this can help. It supports spaces and other special characters in the file paths, but it will work only in bash, GNU find and GNU egrep. You can complement it with these two commands: 1. add executable permission to directories: find . type d -print0 | xargs -0 chmod +x 2. and remove to files: find . type d -print0 | xargs -0 chmod -x Or, in the same loop: while IFS= read -r -u3 -d $'\0' file; do case $(file "$file" | cut -f 2- -d :) in :*executable*|*ELF*|*directory*) chmod +x "$file" ;; *) chmod -x "$file" ;; esac || break done 3< <(find . -print0) Ideas stolen from Greg's wiki: http://mywiki.wooledge.org/BashFAQ/020

Creates the .ssh directory on the remote host with proper permissions, if it doesnt exist. Appends your public key to authorized_keys, and verifies it has proper permissions. (if it didnt exist it may have been created with undesireable permissions). *Korn shell syntax, may or may not work with bash

I simply find binary notation more straightforward to use than octal in this case. Obviously it is overkill if you just 600 or 700 all of your files... Show Sample Output

this requires the use of a throwaway file. it outputs a shell function. assuming the throwaway file is f.tmp usage: >f.tmp;lso f.tmp > f.tmp; . f.tmp;rm f.tmp;lso -l ... notes: credit epons.org for the idea. however his version did not account for the sticky bit and other special cases. many of the 4096 permutations of file permissions make no practical sense. but chmod will still create them. one can achieve the same sort of octal output with stat(1), if that utility is available. here's another version to account for systems with seq(1) instead of jot(1): lso(){ case $# in 1) { case $(uname) in FreeBSD) jot -w '%04d' 7778 0000 7777 ;; *) seq -w 0000 7777 ;; esac; } \ |sed ' /[89]/d s,.*,printf '"'"'& '"'"';chmod & '"$1"';ls -l '"$1"'|sed s/-/./,' \ |sh \ |{ echo "lso(){"; echo "ls \$@ \\"; echo " |sed '"; sed ' s, ,@,2; s,@.*,,; s,\(.* \)\(.*\),s/\2/\1/,; s, ,,'; echo \'; echo }; }; ;; *) echo "usage: lso tmp-file"; ;; esac; } this won't print out types[1]. but its purpose is not to examine types. its focus is on mode and its purpose is to make mode easier to read (assuming one finds octal easier to read). 1. one could of course argue "everything is a file", but not always a "regular" one. e.g., a "directory" is really just a file comprising a list.

This command finds all files in a folder recursively and sets owner and group to read and write. Leaves all dirs intact. This command does takes care of file names with spaces as well.