[ and test are synonyms (except [ requires ]), so you don't want to use [ test:

[ -x /bin/cat ] && echo cat is executable test -x /bin/cat && echo cat is executable 

test returns a zero exit status if the condition is true, otherwise nonzero. This can be replaced by any program to check its exit status:

# echo rarely fails: if /bin/echo hi; then echo 'echo failed'; fi 

If you are using bash (and not sh), you can use [[ condition ]], which behaves more predictably when there are spaces or other special characters in your condition. Otherwise it is the same.

For find, I think you will need to test if any output was generated. -n tests for a non-empty string:

if [[ -n $(find /var/log/crashes -name "app-*.log" -mmin -5) ]] then service myapp restart fi 

A full list of test arguments is available by invoking help test at the bash commandline.

[ and test are synonyms (except [ requires ]), so you don't want to use [ test:

[ -x /bin/cat ] && echo 'cat is executable' test -x /bin/cat && echo 'cat is executable' 

test returns a zero exit status if the condition is true, otherwise nonzero. This can actually be replaced by any program to check its exit status, where 0 indicates success and non-zero indicates failure:

# echoes "command succeeded" because echo rarely fails if /bin/echo hi; then echo 'command succeeded'; else echo 'command failed'; fi # echoes "command failed" because rmdir requires an argument if /bin/rmdir; then echo 'command succeeded'; else echo 'command failed'; fi 

However, all of the above examples only test against the program's exit status, and ignore the program's output.

For find, you will need to test if any output was generated. -n tests for a non-empty string:

if [[ -n $(find /var/log/crashes -name "app-*.log" -mmin -5) ]] then service myapp restart fi 

A full list of test arguments is available by invoking help test at the bash commandline.

_{If you are using bash (and not sh), you can use [[ condition ]], which behaves more predictably when there are spaces or other special cases in your condition. Otherwise it is generally the same as using [ condition ]. I've used [[ condition ]] in this example, as I do whenever possible.}

_{I also changed `command` to $(command), which also generally behaves similarly, but is nicer with nested commands.}

[ and test are synonyms (except [ requires ]), so you don't want to use [ test:

[ -x /bin/cat ] && echo cat is executable test -x /bin/cat && echo cat is executable 

test returns a zero exit status if the condition is true, otherwise nonzero. This can be replaced by any program to check its exit status:

# echo never fails: if /bin/echo hi; then echo 'echo failed'; fi 

If you are using bash (and not sh), you can use [[ condition ]], which behaves more predictably when there are spaces or other special characters in your condition. Otherwise it is the same.

For find, I think you will need to test if any output was generated. -n tests for a non-empty string:

if [[ -n $(find /var/log/crashes -name "app-*.log" -mmin -5) ]] then service myapp restart fi 

A full list of test arguments is available by invoking help test at the bash commandline.

[ and test are synonyms (except [ requires ]), so you don't want to use [ test:

[ -x /bin/cat ] && echo cat is executable test -x /bin/cat && echo cat is executable 

test returns a zero exit status if the condition is true, otherwise nonzero. This can be replaced by any program to check its exit status:

# echo rarely fails: if /bin/echo hi; then echo 'echo failed'; fi 

If you are using bash (and not sh), you can use [[ condition ]], which behaves more predictably when there are spaces or other special characters in your condition. Otherwise it is the same.

For find, I think you will need to test if any output was generated. -n tests for a non-empty string:

if [[ -n $(find /var/log/crashes -name "app-*.log" -mmin -5) ]] then service myapp restart fi 

A full list of test arguments is available by invoking help test at the bash commandline.