File attributes comparisons
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Use the following file comparisons to test various file attributes. You can use the test command or conditional expression using [.
-a file
True if file exists.
Example
[ -a /etc/resolv.conf ] && echo "File found" || echo "Not found"
-b file
True if file exists and is a block special file.
Example
[ -b /dev/zero ] && echo "block special file found" || echo "block special file not found"
OR
[ -b /dev/sda ] && echo "block special file found" || echo "block special file not found"
-c file
True if file exists and is a character special file.
Example
[ -c /dev/tty0 ] && echo "Character special file found." || echo "Character special file not found."
-d dir
True if file exists and is a directory.
Example
#!/bin/bash
DEST=/backup
SRC=/home
# Make sure backup dir exits
[ ! -d $DEST ] && mkdir -p $DEST
# If source directory does not exits, die...
[ ! -d $SRC ] && { echo "$SRC directory not found. Cannot make backup to $DEST"; exit 1; }
# Okay, dump backup using tar
echo "Backup directory $DEST..."
echo "Source directory $SRC..."
/bin/tar zcf $SRC $DEST/backup.tar.gz 2>/dev/null
# Find out if backup failed or not
[ $? -eq 0 ] && echo "Backup done!" || echo "Backup failed"
-e file
True if file exists.
Example
[ -e /tmp/test.txt ] && echo "File found" || echo "File not found"
-f file
True if file exists and is a regular file.
Example
[ ! -f /path/to/file ] && echo "File not found!"
A sample shell script that compare various file attributes and create webalizer (application that generates web pages of analysis, from access and usage log) stats configuration file to given Internet domain name.
#!/bin/bash
# Purpose: A Shell Script To Create Webalizer Stats Configration File
# Written by: Vivek Gite
# ---------------------------------------------------------------------
# Set vars
# Apache vroot for each domain
HTTPDROOT="/home/httpd"
# Path to GeoIP DB
GEOIPDBPATH="/usr/local/share/GeoIP/GeoIP.dat"
# Get the Internet domain such as cyberciti.biz
echo "*** A Shell Script To Create Webalizer Stats Configration File ***"
read -p "Enter a domain name : " DOMAIN
# Make sure we got the Input else die with an error on screen
[ -z $DOMAIN ] && { echo "Please enter a domain name. Try again!"; exit 1; }
# Alright, set some variable based upon $DOMAIN
OUT="$HTTPDROOT/$DOMAIN/stats/webalizer.conf"
CONFROOT="$HTTPDROOT/$DOMAIN/stats"
LOGFILE="$HTTPDROOT/$DOMAIN/logs/access.log"
# Die if configuration file exits...
[ -f $OUT ] && { echo "Webalizer configuration file '$OUT' exits for domain $DOMAIN."; exit 2; }
# Make sure configuration directory exists
[ ! -d $CONFROOT ] && mkdir -p $CONFROOT
# Write a log file
>$OUT
echo "LogFile $LOGFILE" >> $OUT
echo "LogType clf" >> $OUT
echo "OutputDir $CONFROOT/out" >> $OUT
echo "HistoryName $CONFROOT/webalizer.hist" >> $OUT
echo "Incremental yes" >> $OUT
echo "IncrementalName $CONFROOT/webalizer.current" >> $OUT
echo "HostName $DOMAIN" >> $OUT
echo "Quiet yes" >> $OUT
echo "FoldSeqErr yes" >> $OUT
echo "AllSearchStr yes" >> $OUT
echo "HideSite $DOMAIN" >> $OUT
echo "HideSite localhost" >> $OUT
echo "HideReferrer $DOMAIN" >> $OUT
echo "HideURL *.gif" >> $OUT
echo "HideURL *.GIF" >> $OUT
echo "HideURL *.jpg" >> $OUT
echo "HideURL *.JPG" >> $OUT
echo "HideURL *.png" >> $OUT
echo "HideURL *.PNG" >> $OUT
echo "HideURL *.ra" >> $OUT
echo "GroupReferrer yahoo.com/ Yahoo!" >> $OUT
echo "GroupReferrer excite.com/ Excite" >> $OUT
echo "GroupReferrer infoseek.com/ InfoSeek" >> $OUT
echo "GroupReferrer webcrawler.com/ WebCrawler" >> $OUT
echo "SearchEngine .yahoo. p=" >> $OUT
echo "SearchEngine altavista.com q=" >> $OUT
echo "SearchEngine .google. q=" >> $OUT
echo "SearchEngine eureka.com q=" >> $OUT
echo "SearchEngine lycos.com query=" >> $OUT
echo "SearchEngine hotbot.com MT=" >> $OUT
echo "SearchEngine msn.com MT=" >> $OUT
echo "SearchEngine infoseek.com qt=" >> $OUT
echo "SearchEngine webcrawler searchText=" >> $OUT
echo "SearchEngine excite search=" >> $OUT
echo "SearchEngine netscape.com search=" >> $OUT
echo "SearchEngine mamma.com query=" >> $OUT
echo "SearchEngine alltheweb.com query=" >> $OUT
echo "SearchEngine northernlight.com qr=" >> $OUT
echo "CountryFlags yes" >> $OUT
echo "GeoIP yes" >> $OUT
echo "GeoIPDatabase $GEOIPDBPATH" >> $OUT
echo "GraphMonths 72" >> $OUT
echo "IndexMonths 120" >> $OUT
echo "GraphMonths 72" >> $OUT
echo "TopReferrers 20" >> $OUT
echo "TopSites 20" >> $OUT
echo "TopURLs 50" >> $OUT
echo "TopKURLs 50" >> $OUT
echo "Weblizer config wrote to $OUT"
-g file
True if file exists and is set-group-id.
-h file
True if file exists and is a symbolic link.
-k file
True if file exists and its ‘‘sticky’’ bit is set.
-p file
True if file exists and is a named pipe (FIFO).
-r file
True if file exists and is readable.
-s file
True if file exists and has a size greater than zero.
-t fd
True if file descriptor fd is open and refers to a terminal. -u file== True if file exists and its set-user-id bit is set.
-w file
True if file exists and is writable.
-x file
True if file exists and is executable.
-O file
True if file exists and is owned by the effective user id.
-G file
True if file exists and is owned by the effective group id.
-L file
True if file exists and is a symbolic link.
-S file
True if file exists and is a socket.
-N file
True if file exists and has been modified since it was last read. ← String comparison • Home • Shell command line parameters →