-e: Returns true value, if file exists<\/p>\n
-f: Return true value, if file exists and regular file<\/p>\n
-r: Return true value, if file exists and is readable<\/p>\n
-w: Return true value, if file exists and is writable<\/p>\n
-x: Return true value, if file exists and is executable<\/p>\n
-d: Return true value, if exists and is a directory<\/p>\n
File Testing
\n-b filename – Block special file
\n-c filename – Special character file
\n-d directoryname – Check for directory existence
\n-e filename – Check for file existence
\n-f filename – Check for regular file existence not a directory
\n-G filename – Check if file exists and is owned by effective group ID.
\n-g filename – true if file exists and is set-group-id.
\n-k filename – Sticky bit
\n-L filename – Symbolic link
\n-O filename – True if file exists and is owned by the effective user id.
\n-r filename – Check if file is a readable
\n-S filename – Check if file is socket
\n-s filename – Check if file is nonzero size
\n-u filename – Check if file set-user-id bit is set
\n-w filename – Check if file is writable
\n-x filename – Check if file is executable<\/p>\n
example script,<\/p>\n
if a file does not exist<\/p>\n
if [ ! -f \/tmp\/rmohan.txt ]; then
\n echo “File not found!”
\nfi<\/p>\n
#!\/bin\/bash
\nFILE=$1<\/p>\n
if [ ! -f “$FILE” ]
\nthen
\n echo “File $FILE does not exists”
\nfi<\/p>\n
if [[ ! -a $FILE ]]; then
\n echo “$FILE does not exist!”
\nfi<\/p>\n
Also, it’s possible that the file is a broken symbolic link, or a non-regular file, <\/p>\n
like e.g. a socket, device or fifo. If you want to catch that you should:<\/p>\n
if [[ ! -a $FILE ]]; then
\n if [[ -L $FILE ]]; then
\n echo “$FILE is a broken symlink!”
\n else
\n echo “$FILE does not exist!”
\n fi
\nfi<\/p>\n
To reverse a test, use “!”. That is equivalent to the “not” logical operator in other languages. Try this:<\/p>\n
if [ ! -f \/tmp\/test.txt ];
\nthen
\n echo “File not found!”
\nfi
\nOr written in a slightly different way:<\/p>\n
if [ ! -f \/tmp\/test.txt ]
\n then echo “File not found!”
\nfi
\nOr you could use:<\/p>\n
if ! [ -f \/tmp\/test.txt ]
\n then echo “File not found!”
\nfi
\nOr, presing all together:<\/p>\n
if ! [ -f \/tmp\/test.txt ]; then echo “File not found!”; fi
\nWhich may be written (using then “and” operator: &&) as:<\/p>\n
[ ! -f \/tmp\/test.txt ] && echo “File not found!”
\nWhich looks shorter like this:<\/p>\n
[ -f \/tmp\/test.txt ] || echo “File not found!”<\/p>\n
echo “entre file”<\/p>\n
read a<\/p>\n
if [ -s \/home\/rmohan\/$a ] <\/p>\n
then <\/p>\n
echo “yes file is there ” <\/p>\n
else <\/p>\n
echo “soryy file is not there” <\/p>\n
fi<\/p>\n
if [ true ]
\nthen
\n # do something here
\nfi
\nVery important: Make sure you leave spaces around the bracket characters.<\/p>\n
I’ll show more detailed tests as we go along.<\/p>\n
Linux shell file-related tests
\nTo perform tests on files use the following comparison operators:<\/p>\n
-d file Test if file is a directory
\n-e file Test if file exists
\n-f file Test if file is an ordinary file
\n-r file Test if file is readable
\n-w file Test if file is writable
\n-x file Test if file is executable<\/p>\n","protected":false},"excerpt":{"rendered":"
-e: Returns true value, if file exists<\/p>\n
-f: Return true value, if file exists and regular file<\/p>\n
-r: Return true value, if file exists and is readable<\/p>\n
-w: Return true value, if file exists and is writable<\/p>\n
-x: Return true value, if file exists and is executable<\/p>\n
-d: Return true value, if exists and is […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[],"_links":{"self":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/3337"}],"collection":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3337"}],"version-history":[{"count":1,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/3337\/revisions"}],"predecessor-version":[{"id":3338,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/3337\/revisions\/3338"}],"wp:attachment":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3337"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3337"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3337"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}