Linux - File
Table of Contents
1 - About
Linux file management
2 - Articles Related
3 - Basic
4 - Type
4.1 - hidden
Sh - Hidden files
4.2 - Metadata
5 - Management
5.1 - Get
5.1.1 - Filename and extension
Using Parameters Expansion Removal
fileFullName=$(basename "$filePath")
# or
fileFullName="${filePath##*/}"
extension="${fileFullName##*.}"
filename="${fileFullName%.*}"
5.1.2 - parent directory
- From a path string where the file does not exist
VAR=/filedoesnt/exist
echo ${VAR%/*}
/filedoesnt
- dirname returns the first parent of an existing path file.
dirname "dir/file"
dir
5.1.3 - File Permission
5.1.4 - File exist
if [ ! -f $PATH ]; then
echo "File $PATH not found!"
fi
5.1.5 - Absolute path
ABSOLUTE_PATH=$(realpath "${FILE_NAME}")
5.1.6 - Size
with Linux - ls (List directory content)
ls -lh myFile | awk '{ print $5 }'
where:
- -lh shows a human readable size
- an awk will extract the 5de column of the ls output
5.2 - Monitoring the size of a (log) file
Example:
# the program that run
program=unzip
# the log of the progam
logfile='restoreAll.log'
# Don't touch below, the program
count=0
while kill -0 $(pgrep ${program}) 2> /dev/null; do
count=$(( $count + 1 ))
size=$(ls -lh ${logfile} | awk '{ print $5 }')
echo "${count} - Process is running and the log is ${size}"
sleep 10
done
echo "${count} - Process has exited"
5.3 - Comparison
cmp --silent $old $new || echo "files are different"
cmp -b $old $new
See also : diff
5.4 - Diff
5.5 - Filter a list of files ?
- Using grep
This command below gives you all files in the current directory which begin by elfutils
dir | grep -i elfutils
elfutils-0.137-3.el5.i386.rpm
elfutils-devel-0.137-3.el5.i386.rpm
elfutils-devel-static-0.137-3.el5.i386.rpm
elfutils-libelf-0.137-3.el5.i386.rpm
elfutils-libelf-devel-0.137-3.el5.i386.rpm
elfutils-libelf-devel-static-0.137-3.el5.i386.rpm
elfutils-libs-0.137-3.el5.i386.rpm
- find can do it recursviely
5.6 - Remove a file?
Permission: In UNIX and Linux, the ability to remove a file is determined by the access bits of parent directory
chmod 777 .
chown hi-adm:hi-adm .
With the command rm
Example:
- Basic
rm filename.extension
- Prompts for confirmation before removing a file
rm -i filename.extension
- Force removal of the file regardless of it bieng write-protected or open
rm -f filename.extension
- Remove files recursively in 'directory'
rm -r directory
More … perform the man commando
man rm
5.7 - Copy 1 or multiple file
cp - Copy one or more files to another location.
Example::
- Copy of a directory with resistivity:
cp -r dirtocopy newdir
- Copy two files
cp myFile1.txt myFile2.txt myDirDestination
- Copy all files of directory
cp * myDirDestination
# or
cp /myDirSource/* /myDirDestination
- Copy all txt files (with a pattern)
cp *.txt myDirDestination
5.8 - Move / Rename
- mv - Moves or renames file
Example:
mv file.log file.$(date "+%Y.%m.%d-%H.%M.%S").log
5.9 - Concatenate
cat file1 file2 > finalFile
# example with cert
cat first_cert.pem second_cert.pem > combined_cert.pem
5.10 - Transfer
5.11 - See the content
- Shell Data Processing - Head (Displays first 10 lines of file),
- tail - Displays last 10 lines of file,
- Shell Data Processing - Tac (for reverse output) (for reverse output)
- less and more let you scroll the text files
5.12 - Search a file by name
- locate - List files that match a pattern.
Locate all file with a regular expression. In this example all file which begin with sp and end up with the extension msb.
locate -r "sp.*\.msb"
- find - search for files in a directory hierarchy.
find /my/directory -name myFile.extension
5.13 - Search files based on time
touch -d '2011-12-31 10:22' foo
find . -newer foo
See all other files in the time section of the find command
5.14 - Search the content of files
Shell Data Processing - Global Regular Expression Print (GREP command) (line filtering, word search)
- For the current directory .
grep -rn "string*" .
5.15 - File Architecture (32 or 64 bit)
File Architecture
file fileName
Example:
file java
/bin/java: ELF 64-bit LSB executable, AMD x86-64, version 1 (SYSV), for GNU/Linux 2.6.9, dynamically linked (uses shared libs), for GNU/Linux 2.6.9, not stripped
5.16 - Iterate
OLDIFS=$IFS; IFS=$'\n';
filelines=`cat $filename`
for line in $filelines ; do
echo $line
done
IFS=$OLDIFS
5.17 - Security / Capabilty
See setcap - set file capabilities.
A file may also be an executable one and they may got capabilities such as be able to take the port 80
5.18 - Processing
6 - List of command
7 - Content
- Shell Data Processing - Uniq ("unique") - duplicate line removing: returns a file where the line are unique