Logical Operators

• && - Logical AND
• || - Logical OR
• ! - Logical NOT

Integer Comparisons

Traditional numeric comparison operators:

• -eq - Equal
• -ne - Not equal
• -gt - Greater than
• -ge - Greater than or equal
• -lt - Less than
• -le - Less than or equal

Alternative syntax using double parentheses:

(("5" < "10"))

(("7" >= "3"))

String Comparisons

• = or == - String equality (behavior differs in [ ] vs [[ ]])
• != - Not equal
• < - Less than (ASCII comparison)
• > - Greater than (ASCII comparison)
• -z - Test for empty string
• -n - Test for non-empty string

File Teests

• -e - File exists
• -f - Regular file (not directory or device)
• -d - Is a directory
• -h or -L - Is a symbolic link
• -b - Block device
• -c - Character device
• -p - Named pipe
• -S - Socket
• -s - File has non-zero size
• -t - File descriptor connected too terminal ([ -t 0 ] for stdin, [ -t 1 ] for stdout)
• -r - Readable
• -w - Writable
• -x - Executable
• -g - SGID bit set
• -u - SUID bit set
• -k - Sticky bit set
• -O - Owned by current user
• -G - Owned by current group
• -N - Modified since last read
• -nt - Newer than ([ f1 -nt f2 ])
• -ot - Older than ([ f1 -ot f2 ])
• -ef - Hard link to same file ([ f1 -ef f2 ])